Russian President Vladimir Putin and Ukrainian leader Petro Poroshenko met several EU leaders on Friday, but there was little sign of progress in reaching a ceasefire in eastern Ukraine.

Russian President Vladimir Putin and Ukrainian leader Petro Poroshenko met several EU leaders on Friday, but there was little sign of progress in reaching a ceasefire in eastern Ukraine and resolving a dispute over natural gas supplies.

Putin held more than 2-1/2 hours of talks with German Chancellor Angela Merkel overnight. The Kremlin said afterwards the pair were still at odds over how to resolve a crisis that has revived the specter of old Cold War rivalries.

"The two leaders continued to express serious differences in views on the source of Ukraine's domestic conflict, as well as root causes for what is happening there today," the Kremlin said in a statement.

The West has imposed sanctions on Russia for its annexation of Crimea earlier this year and its support of pro-Russian separatists fighting in the east of Ukraine.

European leaders in Milan for a EU-Asia summit, urged Russia to do more to end constant, deadly violations of a ceasefire that was agreed by Putin and Poroshenko last month in Minsk.

"It is obviously above all Russia's task to make clear that the Minsk plan is adhered to," Merkel told reporters on Thursday. "Unfortunately, there are still a lot of shortcomings but it will be important to look for a dialogue here."

Europe fears Russia's decision to cut gas supplies to Ukraine because of unpaid bills could threaten disruptions in the gas flow to the rest of the continent this winter and is working hard to broker a deal.

Russia is Europe's biggest gas supplier, meeting around a third of demand, and the European Union gets about half of the Russian gas it uses via Ukraine.

The stand-off over pricing is the third in a decade between Moscow and Kiev, though this time tensions are higher because of the fighting in eastern Ukraine.