Foreign minister Sikorski has said after three-way talks between Poland, Germany and Russia in St Petersburg that Moscow must stop supporting separatists in eastern Ukraine.

From right: Radoslaw Sikorski, Sergei Lavrov and Frank-Walter Steinmeier: photo - PAP/Paweł Supernak

“If Russia wants to prove that it wants de-escalation in Ukraine, the best way to do it would be to stop the flow of separatists and arms through the Russian-Ukrainian border," Radoslaw Sikorski said after talks with Germany's head of diplomacy Frank-Walter Steinmeier and Russian foreign minister Sergei Lavrov proved inconclusive on Tuesday.

The meeting between the so-called Kaliningrad Triangle countries comes after Ukraine's new president Petro Poroshenko said on Monday that pro-Russian separatists must give up control of several towns and cities in eastern regions and fighting must stop “by the end of the week."

The US and EU have accused Russia of supporting armed separatists in eastern Ukraine, while Moscow has accused the West of stoking up tension in the ex-Soviet state.

During what the Reuters news agency describes as a “tense” news conference after the talks in St Petersburg, Russia's foreign minister said the Kiev government must stop armed operations against the separatists.

"Ending the military operation against the protesters is key, in our view. Nobody is interested in a continuation of war there," said Lavrov. (pg)