Antony Blinken, US Secretary of State, has suggested that diplomacy may still play a role, as Kyiv may decide not to regain all the territories by military means.

"I think there's going to be territory in Ukraine that the Ukrainians are determined to fight for on the ground; there may be territory that they decide that they'll have to try to get back in other ways,"  AFP cites Blinken, answering questions from Congress.

He responded to a question from Republican Representative Chris Stewart, who asked whether the United States supports President Volodymyr Zelenskyy in his efforts to bring back control over Crimea, which was seized and annexed by Moscow in 2014.

"If our commitment and our agreement with Mr Zelenskyy is that we will support you for whatever you want to achieve, including no Russian presence at all in Crimea, then we're asking for a world of hurt," Stewart said.

Blinken stressed that "these have to be Ukrainian decisions about what they want their future to be and how that lands, and how that lands in terms of the sovereignty, the territorial integrity, the independence of the country."

"What we don't want, for everyone's interests, is to have this settle in a place and in a way that simply invites the Russians to rest, rearm and then re-attack," Blinken said.

NATO Secretary General Jens Stoltenberg commented on the possibility of the reclamation of Crimea by Ukraine by force by pointing out that the war should end at the negotiations table, where Ukraine will make a decision about acceptable conditions on its own.