Russian President Vladimir Putin ratcheted up tensions with Europe on Tuesday, warning that if the bloc sparked a war with Russia, Moscow was prepared to meet it.

Vladimir Putin hosted US negotiators at the Kremlin on Tuesday for five hours of talks aimed at ending the war in Ukraine, which a Russian official said had been "productive".

Putin earlier said Europe's peace deal demands were "not acceptable", adding: "We are not going to fight with Europe, but if Europe wants to fight with us, we are ready right now"