The Deputy Permanent Representative of Ukraine to the United Nations told members of the Security Council that it has reviewed a "draft" U.S. peace plan to end its war with Russia, but that it would not give away any territory.

"There will never be any recognition, formal or otherwise, of Ukrainian territory temporarily occupied by the Russian Federation. Our land is not for sale," said Khrystyna Hayovyshyn, Ukraine's UN representative.

The statement comes after reports that the U.S. and Russia drew up a plan aimed at ending the war in Ukraine that calls for major concessions from Kyiv, according to a person familiar with the matter, including granting some demands the Kremlin has made repeatedly since the full-scale invasion began nearly four years ago.

The proposal, which could still change, calls, in part, for Ukraine to cede territory to Russia and to abandon certain weaponry, according to the person familiar with the matter, who had been briefed on the contours of the plan but was not authorized to comment publicly.

It would also include the rollback of some critical U.S. military assistance.

Russia, as part of the proposal, would be given effective control of the entire eastern Donbas region, Ukraine's industrial heartland made up of the Donetsk and neighboring Luhansk regions, even though Ukraine still holds part of it.

Russian President Vladimir Putin has listed the capture of the Donbas as the key goal of the invasion.

But a peace deal that requires Kyiv to hand over territory to Russia would not only be deeply unpopular with Ukrainians, it also would be illegal under Ukraine's constitution.

Ukrainian President Volodymyr Zelenskyy has repeatedly ruled out such a possibility.