President Biden met with his national security team Saturday amid reports that Russia was planning to install a pro-Kremlin leader in Ukraine.

One U.S. official told Fox News the reports were "deeply concerning."

Late Saturday, the White House posted a photo on social media, showing Biden and advisers at Camp David, Maryland, where they gathered to discuss "continued Russian aggressive actions toward Ukraine."

The president "affirmed that if Russia further invades Ukraine, the United States will impose swift and severe consequences on Russia with our Allies and partners," the White House post said.

RUSSIA, NATO MAINTAIN DICEY IMPASSE, EXPERTS DIVIDED ON BEST NEXT STEPS

Earlier Saturday, the U.K.'s Foreign, Commonwealth & Development Office disclosed it had information suggesting the Russian plan was in the works.

"We have information that indicates the Russian Government is looking to install a pro-Russian leader in Kyiv as it considers whether to invade and occupy Ukraine," a spokesperson for the British agency said.

Former Ukrainian Member of Parliament Yevhen Murayev was being considered a potential candidate, the spokesperson added.

Murayev heads Nashi, a small pro-Russian political party that currently has no representation in Ukraine's parliament, The Associated Press reported.

The U.K. government said its claim was based on an intelligence assessment, but it provided no evidence to support it, according to the AP.

Britain has sent anti-tank weapons to Ukraine a part of efforts to help the country defend against a potential Russian attack.

A U.S. official reacted to the reports regarding Russia and Ukraine.

NATO SENDING FIGHTERS, SHIPS TO REGION; UK TO WITHDRAW SOME STAFF FROM EMBASSY IN UKRAINE

Russian President Vladimir Putin attends a Security Council meeting in Moscow, Russia, Monday, Dec. 25, 2017. (Alexei Nikolsky, Sputnik, Kremlin Pool Photo via AP)

Russian President Vladimir Putin is seen in an undated photo. A spokesperson for the U.K.'s Foreign, Commonwealth & Development Office said Saturday that the agency had information indicating the Russian government was looking to install a pro-Russian leader in Ukraine. (Associated Press)

"This kind of plotting is deeply concerning," Emily Horne, a spokeswoman for the White House National Security Council, told Fox News.

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"The Ukrainian people have the sovereign right to determine their own future, and we stand with our democratically elected partners in Ukraine," Horne said.

The U.S. has worked in recent months to unify its European allies against Russian aggression in Ukraine.

Fox News' Patrick Ward and Jennifer Griffin and The Associated Press contributed to this story.