Russian President Vladimir Putin and Ukrainian President-elect Petro Poroshenko have called for a quick end to the bloodshed in eastern Ukraine, Russian officials have said.

The two leaders were meeting for the first time since Mr Poroshenko's election, at a D-Day event in France.

Immediate ceasefire was vital to create conditions for talks, Mr Putin said.

Separately US President Barack Obama spoke to Mr Putin of the need to de-escalate the situation.

Fighting continues, with government forces reportedly launching a tank attack near rebel-held Sloviansk.

The Ukrainian authorities have announced an "active phase" of what they call an anti-terrorist operation in and around Sloviansk, which was seized by pro-Russian militants several weeks ago.

The BBC's Steve Rosenberg, who was near the town on Thursday, says it was clear Ukrainian forces had encircled it and moved in a lot of weaponry.

Separately, Ukrainian media reported that one member of the security forces had been killed and several wounded in a mortar attack outside the city.

The three leaders are said to have chatted for about 15 minutes, in between a photo for world leaders and a meal organised by French President Francois Hollande.

"During the brief conversation, both Putin and Poroshenko called for a quick end to the bloodshed in south-eastern Ukraine, and also to military activity by both sides", said Kremlin aide Dmitry Peskov.

"It was also confirmed that there is no alternative to settling the situation by peaceful political means."