National Security Adviser Robert O'Brien said in an interview with CBS News said he couldn't "commit the United States" to keep providing lethal aid to Ukraine forever.

Asked by a CBS host, whether he believes the U.S. policy toward Ukraine implies provision of lethal aid until Russia stops backing its proxy forces in Donbas and backs out of Crimea, O-Brien said: "I'm not going to get into hypotheticals about what could happen down the road.

He added that "hopefully Russia and Ukraine can get along and there can be some sort of a peace treaty and an agreement between them."

"So I'm not going to commit the United States to what we're going to do forever," the national security adviser stressed, noting that "for right now, we're set."

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He noted that Donald Trump's administration is the first one "to send lethal military aid to Ukraine."

"I think that's very important," O-Brien said.

As UNIAN reported reported, the U.S. State Department has unblocked a $141 million-worth military assistance to Ukraine even before President Donald Trump on September 11 announced the lift of the relevant suspension.

U.S. Congress allocated $250 million to the Department of Defense for an initiative to support Ukraine’s security. According to reports, President Trump in July 2019 asked Mick Mulvaney, the current acting chief of staff of the White House, to put Ukraine assistance on hold.