President Joe Biden's top national security adviser said Sunday that the White House had not yet seen China provide Russia with lethal assistance in its war on Ukraine and warned Beijing that doing so would be against its interests.
"We have not seen China yet provide military equipment to Russia for purposes of fighting in the war in Ukraine. We haven't seen it yet," White House national security adviser Jake Sullivan said on NBC News' "Meet the Press."
"We're continuing to watch. We'll stay vigilant, as President Biden said, but so far, we haven't seen it," Sullivan said.
Sullivan added, "I don't think it is in China's interest to do this."
The U.S. was reported to believe China is considering sending artillery and ammunition to Russia.
"I think it would alienate them from a number of countries in the world, including our European allies, and it would put them for square into the center of responsibility for the kinds of war crimes and bombardments of civilians and atrocities that the Russians are committing in Ukraine," Sullivan said, adding that "their weapons would in effect be used for the slaughter of people in Ukraine."
"But that's a decision Beijing is going to have to make for itself," he said.
Sullivan said that the U.S. would remain "vigilant" in monitoring developments and that communicating possible consequences to Beijing for providing such assistance to Russia "is better done directly with Chinese counterparts in private."
More from NBC News:
U.S. Energy Department assesses with 'low confidence' Covid may have originated from Chinese lab leak
With Trump running, nearly all Republican senators say no to a presidential bid
News outlets request McCarthy share Jan. 6 footage that Tucker Carlson says he has access to
NBC News reported that intelligence suggests China is considering sending artillery and ammunition to Russia, according to three current U.S. officials, a Western official and a former U.S. official briefed about the intelligence. The officials would not say what specific evidence they have to support their claims.
China's Foreign Affairs Ministry did not respond to an earlier request for comment on the intelligence.
The Wall Street Journal was first to report details of what the U.S. believes Beijing is considering.
In an exclusive NBC News report this month, four U.S. officials familiar with the matter said the administration is worried Beijing is considering sending lethal aid. Asked by Bloomberg about reports of possible lethal assistance to Russia, a spokesman for the Foreign Affairs Ministry said, "We will never accept U.S.'s criticism, even coercion and pressure on China-Russia relations."
After the U.S. downed a suspected spy balloon over the Atlantic Ocean on Feb. 4, China declined Washington's request for a secure call between Defense Secretary Lloyd Austin and his counterpart, National Defense Minister Wei Fenghe, the Pentagon said.
A Chinese fighter jet flew within 500 feet of a U.S. Navy plane over the South China Sea last week. U.S. officials said encounters like that have become more frequent as Beijing and Washington increase their efforts to wield influence in the Pacific.
The incidents have contributed to escalating tensions between the world's two largest economies.
Sullivan stressed the importance of establishing adequate military communications between the countries Sunday.
"We have said repeatedly that we need to have military communications channels to avoid escalation, to avoid surprise, to avoid mistakes, and it is unfortunate that the Chinese defense ministry has declined to take calls from the U.S. secretary of defense. That's on China," Sullivan said.
"It is not that all lines of communication are cut or shut off," Sullivan added, noting Secretary of State Antony Blinken's meeting in Munich this month with a senior Chinese diplomat. "Rather, that we do not have the military-to-military exchanges that we think are necessary to ensure stability."
Sullivan also addressed why the White House has declined calls from lawmakers from both major parties to provide Ukraine with F-16 fighter jets, saying such a possibility was for "another phase" of the war.
"The question of F-16s is really a question for another day, for another phase," he said. "This phase is about ground combat and being able to have the tools in the hands of the Ukrainians to take the territory back that the Russians are occupied."