US President Joe Biden said he has clearly warned Russian President Vladimir Putin against invading Ukraine, threatening that Russia would pay a "terrible price" and face devastating economic consequences.

In Delaware, Biden told reporters that the possibility of sending US forces to Ukraine was "never on the table."

Earlier, Biden said the United States would provide additional defense aid to Kiev beyond what it currently provides and support NATO allies in the Alliance's eastern flank.

"The idea the United States is going to unilaterally use force to confront Russia invading Ukraine is not on the cards right now," Biden stressed. "We have a moral obligation and a legal obligation to our NATO allies under Article Five. It's a sacred obligation. That obligation does not extend to... Ukraine."

Russia has the right to defend its security

Russian President Vladimir Putin said earlier that Moscow pursues a peaceful foreign policy but has the right to defend its security in the medium and long terms.

Speaking publicly for the first time since his talks with US President Joe Biden, the Russian President added that his recent online meeting with US President Joe Biden was "open and constructive."

"The conversation was open, substantive, and constructive... We have the opportunity to continue this dialogue, it seems to me… this is the most important thing," Putin stressed.

Kremlin described the talks as "frank" and said the Russian President requested Washington to provide guarantees NATO would not continue its eastward expansion.

The Biden administration had prepared $200 million worth of aid to Ukraine over the past few weeks but postponed it to give diplomacy a chance for a possible easing of tensions between Kiev and Moscow.