UK says Ukraine war 'taking a heavy toll' on Russia's advanced units; Biden announces new military aid package for Ukraine. Follow our live updates

The Ukraine conflict is heavily affecting some of Russia's most capable units, said the U.K.'s Defence Ministry in its daily intelligence update.

"The conflict in Ukraine is taking a heavy toll on some of Russia's most capable units and most advanced capabilities," the ministry said in its update, posted on Twitter.

"It will take considerable time and expense for Russia to reconstitute its armed forces following this conflict," it added.

At least one T-90M, Russia's most advanced tank, has been destroyed in fighting, the update said.

"It will be particularly challenging to replace modernised and advanced equipment due to sanctions restricting Russia's access to critical microelectronic components," the ministry added.

— Weizhen Tan

Ukrainian President Volodymyr Zelenskyy told London think-tank Chatham House that any peace deal with Moscow would be dependent on Russian forces pulling back to their positions before the war, the BBC reported.

Zelenskyy said that was the minimum that Ukraine could accept, according to the report. He added that there could be no question of Russia holding on to territory it has taken since the invasion started.

"I was elected by the people of Ukraine as president of Ukraine, not as president of a mini Ukraine of some kind. This is a very important point," he said, according to the BBC report.

— Weizhen Tan

The Italian government froze a yacht with reported links to Russian President Vladimir Putin, blocking the vessel from leaving its port.

The Italian Finance Ministry said an investigation found "significant economic and business links" between the yacht's beneficial owner and "prominent elements of the Russian government" and people sanctioned over Moscow's 2014 annexation of Crimea. Italy did not name Putin, but various reports have linked the Russian leader to the vessel.

The ownership of the yacht has "long been under the attention of the authorities," the finance ministry said in a statement.

The Cayman Island-flagged superyacht Scheherazade extends nearly 460 feet and is currently moored in the Italian port of Marina di Carrara.

— Amanda Macias

President Joe Biden announced a new U.S. military assistance package for Ukraine as its tries to fight off a sustained Russian invasion.

The aid tranche will be the ninth the Biden administration has sent to Ukraine since Moscow invaded its neighbor in late February.

The White House did not specify a dollar amount for the package.

— Amanda Macias

Ukrainian President Volodymyr Zelenskyy will attend a virtual G-7 group of nations meeting on Sunday, White House press secretary Jen Psaki told reporters traveling on Air Force One.

Psaki said the meeting will be chaired by German Chancellor Olaf Scholz, and that the leaders are expected to discuss the latest developments in Russia's war against Ukraine.

She said the leaders will also discuss additional ways to show "support for Ukraine and Ukraine's future and demonstrating continued G-7 unity in our collective response, including building on our unprecedented sanctions to impose severe costs for Putin's war."

Psaki declined to elaborate on additional sanctions measures when pressed by reporters.

— Amanda Macias

The European Union's foreign affairs chief has voiced worry that Russia might expand its war in Ukraine to include Moldova, a small nation that borders southern Ukraine.

Josep Borrell, the top EU diplomat, was asked at a forum in Florence, Italy, if the European Union was concerned about what could happen to Moldova.

"Yes, we're very much worried about what can happen," Borrell said. "The temptation to expand the war and affect Moldova is a possibility,'' Borrell said.

He cited recent explosions in the country as well as the presence of Russian troops. Last month, two explosions in a radio facility close to the border with Ukraine knocked out of service a pair of powerful broadcast antennas in Moldova's separatist region of Transnistria, according to local police.

Transnistria is a narrow strip of land that has been under the control of separatist authorities since a 1992 war with Moldova. Russia bases some 1,500 troops in the breakaway region, describing them as peacekeepers.

— Associated Press

— Reuters

Nearly 25 million tons of grains are stuck in Ukraine and unable to leave the country due to infrastructure challenges and blocked Black Sea ports including Mariupol, a U.N. food agency official said.

The blockages are seen as a factor behind high food prices which hit a record high in March in the wake of Russia's invasion of Ukraine, before easing slightly in April, the FAO said.

Ukraine had been the world's fourth largest exporter of maize (corn) in the 2020/2021 season and the number six wheat exporter, according to International Grains Council data.

"It's an almost grotesque situation we see at the moment in Ukraine with nearly 25 million tons of grain that could be exported but that cannot leave the country simply because of lack of infrastructure, the blockade of the ports," Josef Schmidhuber, FAO Deputy Director, Markets and Trade Division told a Geneva press briefing via Zoom.

— Reuters

Pentagon spokesman John Kirby dismissed claims that the U.S. was fighting a proxy war in Ukraine following a series of intelligence leaks that link the U.S. to some of the more impressive battlefield blows.

Kirby said that intelligence leaks play into the Kremlin's propaganda handbook that the U.S. is waging a war against Russia through Ukraine and other European countries.

"Dmitry Peskov, the [Kremlin] spokesman said something similar just yesterday, acknowledging that this is just the United States now involved in some sort of proxy effort. So it's not helpful," Kirby told MSNBC's "Morning Joe."

Kirby said he would not "get into specifics" when asked about a New York Times report claiming the Pentagon was giving Ukraine intelligence that helped kill key Russian generals and an NBC News report saying the U.S. helped sink the Russian warship Moskva. CNBC and NBC News could not verify the New York Times report.

"What I can tell you is we didn't provide them specific targeting information for that ship and we were not involved in their decision to strike that ship," he said of the NBC News report.

On Thursday, Kirby said from the Pentagon podium that the U.S was not tracking the movements of key Russian generals on the battlefield. But he did not explicitly deny that U.S. intelligence shared with Kyiv allowed Ukrainian forces to put the two together.

— Amanda Macias

Ukrainian President Volodymyr Zelenskyy has said that only the delivery of the necessary weapons will be able to lift the Russian siege of Mariupol, adding that the relevant authorities are working to evacuate people as much as they can.

Speaking at an online event hosted by U.K. think tank Chatham House, Zelenskky said the southeastern port city of Mariupol had been destroyed by the "sheer cruelty" of Russian forces.

"There is nothing there to fall apart. It is already devastated. There is no place. There is no structure. It is all destroyed completely," Zelenskky said of Mariupol, according to a translation.

"I understand that Russia would like to have a parade for the 'Victory Day' on the 9th of May ... but only weapons will deblock this region — when and if we have the necessary equipment," he added.

— Sam Meredith

The United Nations has confirmed 3,309 civilian deaths, including at least 234 children, in Ukraine since Russia invaded its ex-Soviet neighbor on Feb. 24.

The agency also reported 3,493 civilian injuries in the conflict so far.

The Office of the UN High Commissioner for Human Rights said the death toll in Ukraine is likely higher, because the armed conflict can delay reports.

The international body said most of the civilian casualties recorded were caused by the use of explosive weapons with a wide impact area, including shelling from heavy artillery and multiple launch rocket systems, as well as missiles and airstrikes.

— Amanda Macias

The head of Kyiv's military administration has warned that Russia could resume its offensive in the Kyiv region, saying authorities are preparing for such a scenario.

In an interview with Ukrinform news agency, Oleksandr Pavlyuk said Russia cannot claim a complete victory over Ukraine without the capture of its capital city.

"Therefore, if Russia's plans remain the complete destruction of Ukraine, as it has always been, and as long as Russia exists, Ukraine's heart will be in focus. We do not reject such options, we calculate and prepare for various possible scenarios of the enemy's actions," Pavlyuk said, according to a translation.

— Sam Meredith

Ukrainian media is reporting Russian naval ship Admiral Makarov is on fire in the Black Sea.

Oleksiy Honcharenko, a member of Ukraine's parliament, suggested via Telegram that the frigate was in distress and may be heading for the same fate as Russia's flagship missile cruiser Moskva — which sunk on April 14 after being struck by two Ukrainian Neptune anti-ship missiles.

CNBC has not been able to independently verify the claims.

— Sam Meredith

Germany will deliver seven self-propelled howitzers to Ukraine, on top of five such artillery systems the Dutch government already pledged, German Defence Minister Christine Lambrecht said on Friday.

Germany reversed its long-held policy of not sending heavy weapons to war zones last week following pressure at home and abroad for it to help Ukraine fend off Russian attacks.

The heavy weapons will come out of the Bundeswehr inventories and be delivered as soon as they emerge from maintenance over the next weeks, Lambrecht and her chief of defence, general Eberhard Zorn, told reporters in the Slovak town of Sliac.

— Reuters

Ukraine's head of presidential office says a new attempt to evacuate people from Mariupol's Azovstal steel plant is underway.

"The next stage of rescuing our people from Azovstal is underway at the moment," Andriy Yermak said via Telegram, according to a translation. "Information about the results will be provided later."

— Sam Meredith

Russian forces in the besieged coastal city of Mariupol have continued their ground assault on the Azovstal steel plant for a second day, according to the U.K. Defense Ministry, despite Russian statements claiming they would only seek to seal it off.

The renewed effort to secure Azovstal and complete the capture of Mariupol is likely linked to Russia's annual "Victory Day" commemorations on May 9, the U.K. said, and President Vladimir Putin's desire to have a "symbolic success" in Ukraine.

This sustained effort "has come at personnel, equipment and munitions cost to Russia," the U.K. ministry said in its latest intelligence update.

— Sam Meredith

Former U.S. President George W. Bush and Ukrainian President Volodymyr Zelenskyy met via an online video conference, where Zelenskyy invited Bush to visit Ukraine.

Bush in turn conveyed his support for the president and the people of Ukraine.

"Your courage is very important for further success. If you continue to do what you do, you will always have our support if you continue to fight as you do now," he said, according to the Ukrainian president's office.

Bush also called Zelenskyy "the Winston Churchill of our time," according to a statment from the George W. Bush Presidential Center.

Zelenskyy expressed his appreciation for support from the U.S. and Americans.

"Americans are sincere, open-minded people, and I feel it. We have common values. I feel that it is from the heart," Zelenskyy said, according to the president's office.

— Chelsea Ong

United Nations Secretary-General Antonio Guterres said he told both Ukrainian leader Volodymyr Zelenskyy and Russian President Vladimir Putin that the Kremlin's invasion must end for the sake of the entire world.

"Throughout my travels, I did not mince words," Guterres told the United Nations Security Council, following separate trips to the capitals of Russia and Ukraine.

"I said the same thing in Moscow as I did in Kyiv which is exactly what I have repeatedly expressed in New York. Namely that Russia's invasion of Ukraine is a violation of its territorial integrity and of the charter of the United Nations. It must end for the sake of the people of Ukraine, Russia, and the entire world," he said.

Guterres said that one goal of his trip was to broker the safe passageway of Ukrainians trapped in a steel plant in Mariupol. He said that so far, nearly 500 civilians have been evacuated after living under relentless shelling and scarce availability of food and water.

Guterres said that a third evacuation was underway but declined to elaborate in order to "avoid undermining possible success."

— Amanda Macias

Intelligence shared by the U.S. helped Ukraine sink the Russian cruiser Moskva, U.S. officials told NBC News, confirming an American role in perhaps the most embarrassing blow to Vladimir Putin's troubled invasion of Ukraine.

A guided-missile cruiser carrying a crew of 510, the Moskva was the flagship of Russia's Black Sea Fleet. It sank on April 14 after being struck by two Ukrainian Neptune anti-ship missiles, U.S. officials said. Moscow said the vessel sank after a fire. 

The attack happened after Ukrainian forces asked the Americans about a ship sailing in the Black Sea south of Odesa, U.S. officials told NBC News. The U.S. identified it as the Moskva, officials said, and helped confirm its location, after which the Ukrainians targeted the ship.

The U.S. did not know in advance that Ukraine was going to target the Moskva, officials said, and was not involved in the decision to strike. Maritime intelligence is shared with Ukraine to help it defend against attack from Russian ships, officials added.

Read the full story here.

— Ken Dilanian, Courtney Kube and Carol E. Lee, NBC News

U.S. intel helped Ukraine sink Russian flagship Moskva, officials say; U.S. announces more humanitarian aid