Russian Foreign Minister Sergei Lavrov has told his US counterpart John Kerry that the US should use its influence to make Ukraine's government immediately stop military operations in south-east Ukraine, the Russian foreign ministry said.
Lavrov also said that it was important that the mediating role of the Organisation for Security and Co-operation in Europe (OSCE) was increased to secure Kiev's fulfilment of the Geneva declaration on de-escalating tensions in Ukraine.
"Chances of this still exist," the ministry said in a statement, as long as all Ukrainian regions are represented in a national dialogue on constitutional reform, and "terrorists" from the Right Sector - a Ukrainian nationalist group in western Ukraine - group are curbed.
Lavrov, in a phone conversation with German Foreign Minister Frank-Walter Steinmeier, also said he was concerned about reports that Ukraine's army was preparing to storm cities in south-east Ukraine including Slaviansk, according to a statement from the foreign ministry.
The town of Slaviansk in eastern Ukraine has been turned into heavily fortified redoubt by pro-Russian separatists.
On Saturday Ukraine said it was pressing on with an offensive in the area for a second day, and had recaptured a television tower and a security services building from rebels in Kramatorsk, a town near the rebel stronghold of Slaviansk.
Steinmeier agreed that violence should halt, the statement said.
