Russian President Vladimir Putin on Wednesday appeared to rule out a full ceasefire in Ukraine, saying that Kiev would use any pause in the fighting to rearm.

Ukraine has been pushing for an unconditional and immediate 30-day truce, issuing its latest proposal to Moscow at peace talks in Istanbul on Monday.

"Why reward them by giving them a break from the combat, which will be used to pump the regime with Western arms, to continue their forced mobilisation and to prepare different terrorist acts," Putin said in a televised government meeting.

At talks on Monday, Russia outlined maximalist demands for such a ceasefire, including that Ukraine fully withdraws from four regions across its east and south that Moscow claims to have annexed.

Attacks on bridges

Putin also accused Ukraine of being behind "terrorist" attacks on bridges in its border regions over the weekend, including one that caused a train to derail, killing seven people.

That attack – which Ukraine has not claimed responsibility for – was "directed at thwarting the negotiation process", Putin said.

Russia instead proposed on Monday a short two-three day ceasefire intended to let both armies collect the bodies of dead soldiers from the battlefield.

Russian Foreign Minister Sergei Lavrov told Putin that Kiev had rejected that idea.

'Gross mistake'

"I believe this is simply a gross mistake on the part of the regime in Kiev," he said.

Russia's top negotiator, Vladimir Medinsky confirmed that Moscow was ready to go ahead with a large-scale prisoner exchange, agreed in Istanbul, on June 7-9, after Ukraine's President Volodymyr Zelenskyy said the first stage would take place this weekend.