The leaders of Russia, Ukraine, France and Germany have reached a ceasefire deal after 17 hours of talks on the Ukrainian conflict.

Speaking at a press conference in the Belarusian capital, Minsk, Russia’s president, Vladimir Putin, said the ceasefire would come into force on Sunday.

But he signalled that a number of key issues remained unresolved, including the location of the Ukraine-Russia border, the rights of native Russians in eastern Ukraine and the withdrawal of troops and heavy weapons.

"The next thing that I believe is very important is the withdrawal of heavy weapons ... and the withdrawal of Donbass militias,” he said.

Putin added: "There is also the political settlement. The first thing is constitutional reform that should take into consideration the legitimate rights of people who live in Donbass. There are also border issues. Finally there are a whole range of economic and humanitarian issues.”

The French president, François Hollande, confirmed that a ceasefire had been agreed. He said much work still needed to be done, but that an agreement in Minsk was a real chance to ameliorate the situation. 

Hollande and the German chancellor, Angela Merkel – who was also took part in the marathon talks – would ask the European Union to support the agreement later on Thursday.

Merkel’s spokesman, Steffen Seibert, said on Twitter: "After 17 hours, negotiations in Minsk have finished: ceasefire from 15 February, then withdrawal of heavy weapons. Therein lies hope.”

Under the terms of the deal reached in Minsk, the leaders of Ukraine, Russia, Germany and France committed to respect Ukraine’s sovereignty and territorial integrity. They also agreed that regular meetings would be held to ensure the fulfilment of the agreements, the Russian-distributed document said.

Earlier, Ukraine had played down speculation about a possible ceasefire agreement, accusing Russia of imposing "unacceptable” conditions.

At one point during the negotiations Putin signalled his apparent frustration at the lack of progress by snapping a pen or a pencil.

More than 5,300 people have died since April in the conflict between Ukrainian forces and Russia-backed separatists in two eastern provinces, and the bloodshed rose sharply in recent weeks.

The US president, Barack Obama, has faced rising calls at home to send military aid to Ukraine, but European leaders fear it would only aggravate the violence. Russia, meanwhile, faces a severe economic downturn driven in part by sanctions the west has imposed for supporting the separatists with troops and equipment, which Moscow vehemently denies it is doing.

In a diplomatic blitz that began last week, Merkel and Hollande visited Kiev and Moscow to speak to Poroshenko and Putin, paving the way for the marathon session in Minsk.

"The entire world is waiting to see whether the situation moves toward de-escalation, weapons pullback, ceasefire, or ... spins out of control,” Poroshenko said upon arriving.

A top rebel official, Andrei Purgin, told Russian television that it might take a day or more for hostilities to end even if a ceasefire was called.

On Wednesday the French foreign minister, Laurent Fabius, said "quite a number of problems remain” in negotiations including the future of eastern Ukraine, guarantees about the Ukraine-Russia border and the prospects of a possible ceasefire, weapons pullback and prisoner exchange.

Fabius said the aim of the talks was to win an accord that works on the ground, "not just one on paper.”

Germany and France rushed to mediate after a recent surge in fighting that continued on Wednesday. In the rebel-held city of Donetsk, rebel officials said five people were killed and nine wounded in a shelling attack on a bus station. An Associated Press reporter saw one body.

Officials in Kiev said 19 troops were also killed and 78 wounded in fighting in Debaltseve, a hotly contested transport hub in eastern Ukraine.