Ukraine accused Russia of allowing three tanks and other military vehicles to cross into Ukraine to help pro-Russian separatists.
Here's what Obama's critics get wrong — and the risk they pose for the next president, says Harvard Professor Joseph Nye.
Western officials hope that informal contacts between Putin and Poroshenko during the event can help ease tensions over Ukraine's future.
Hollande will meet Obama in a restaurant overlooking the iconic Champs-Elysees before going back to his residence for a supper with Putin.
In a joint press conference with British Prime Minister David Cameron, President Obama announces the G-7 nations stand united in support of Ukraine.
Ukraine doesn't like being dependent on Russia for much of its energy, but it may have no choice for now.
Angela Merkel has asked France whether it would be willing to put forward Christine Lagarde as president of the European Commission, two sources said.
The world's leading industrialized nations meet without Russia for the first time in 17 years on Wednesday.
Alastair Newton, Senior Political Analyst at Nomura, says signs of compromise over unpaid gas debts between Russia's Gazprom and Ukraine's Naftogaz has defused tensions in eastern Europe.
Brian Singer, head of dynamic allocation strategies team at William Blair & Co., discusses how geopolitical events influence markets and explains why the current environment is supportive of Spanish and Italian equities.
Russia has called an emergency meeting of the U.N. Security Council to introduce a resolution calling for an immediate cease-fire in Ukraine.
The slow recovery and wealth inequality are fueling political and religious extremism and, in some cases, outright terrorism, says Nouriel Roubini.
Jesse Sherman, portfolio manager at Renaissance Asset Management, says Russia will tread a fine line on the political front.
The latest CNBC Global CFO Council survey shows that corporate tax reform is a must, but there is little chance that change will come soon.
Helima Croft, Barclays managing director, discusses how sanctions by the West have impacted Russia and Ukraine. And Walter Isaacson, The Aspen Institute, weighs in on Putin's role in controlling the oil there.
They already know what rock'n'roll is worth, so now Britain's statisticians are getting to grips with sex and drugs in a bid to give a broader view of the economy.
CNBC's Robert Frank looks at the history of billionaires as democratic leaders.
CNBC's Steve Sedgwick reports the latest on the crisis in Ukraine after the country elected billionaire Petro Poroshenko to President-elect.
Vladimir Putin's disruptive moves in Ukraine are aimed at keeping his grip on power in Moscow, said hedge fund boss William Browder, in reaction to CNBC's interview with the Russian leader.
John Herbst, former U.S. Ambassador to Ukraine, shares his thoughts on the Ukrainian elections and whether President-elect Petro Poroshenko is able to handle the turmoil in the East.