Sergei Lavrov, the foreign minister, said today that if the plan “erased...key understands” that Putin and Donald Trump had reached in Alaska earlier this year, the “situation will be fundamentally different”.

At that summit, Mr Trump agreed to push Ukraine to surrender to the remainder of the Donbas region not currently under Russian military control.

It emerged last week that the US and Russia had formulated a 28-point peace plan to end the war, though this was revised down to 19 points following talks between American and Ukrainian officials in Geneva on Sunday.

Dan Driscoll, the US army secretary, is currently holding negotiations with separate Russian and Ukrainian delegations in Abu Dhabi.

“After Anchorage, when we thought these understandings had already been formalised, there was a long pause. And now the pause has been broken by the introduction of this document . . . A whole series of issues there, of course, require clarification,” Lavrov said today.