U.S. national security adviser Jake Sullivan (C) speaks with Andriy Yermak (L), head of the Office of the President of Ukraine, in Istanbul on Sunday. Photo courtesy of Andriy Yermak/Twitter
Oct. 2 (UPI) -- The United States told Ukraine on Sunday that it will impose "severe costs" on anyone who supports Russia's attempts to annex four regions in eastern and southern Ukraine.
U.S. national security adviser Jake Sullivan issued the reiteration of U.S. support for Kyiv during a meeting in Istanbul on Sunday with Andriy Yermak, head of the Office of the President of Ukraine, the White House said in a statement.
Sullivan "conveyed that the United States and its allies and partners will not be deterred by Russia's flagrant violations of international law, including the United Nations Charter, and will impose costs on any individual, entity or country that provides support to Russia's purported annexation," the readout of the meeting said.
The meeting was held two days after Russian President Vladimir Putin declared the annexation of Donetsk, Lugansk, Zaporozhye and Kherson following the completion of referendums that have been widely denounced as a sham.
During a speech on Friday, the Russian president pointed to the referendums in support of his annexation attempts, stating "this is the will of millions of people."
According to the White House, Sullivan and Yermak also discussed the situation at Ukraine's Zaporizhzhia Nuclear Power Plant after Ihor Murashov, the director of the plant, was detained by Russia as well as Ukraine's work with the United nations to export food.
"Sullivan emphasized the United States is committed to supporting the Ukrainian people as they defend their sovereignty and democracy," the White House said.
Since Putin announced his attempt annex the four regions, several democratic nations have responded with sanctions, including the United States, Canada, Australia and Britain.
In response Russia's move, Ukraine also announced that it has applied to join NATO. Putin has blamed expansion of the defensive military alliance for his invasion of Ukraine.