Marathon talks in Belarus have secured a deal on a roadmap to peace, including a ceasefire, in Ukraine's war with pro-Russian separatists after negotiations through the night to halt the spiralling bloodshed.
President Vladimir Putin emerged from the summit with French President Francois Hollande, German Chancellor Angela Merkel and Ukrainian President Petro Poroshenko on Thursday, saying they had reached agreement on the "main" points.
Putin said a ceasefire would take effect on Sunday, February 15, and that heavy weapons would be withdrawn from front lines of the conflict, which has already killed at least 5,300 people and driven hundreds of thousands from their homes.
Hollande said there was agreement on "a comprehensive political solution", adding that there was "serious hope, even if all is not done".
Hollande and Poroshenko stressed that separatist leaders had signed the truce, meant to replace an earlier ceasefire agreement reached in Minsk in September but rarely observed.
Al Jazeera's Rory Challands, reporting from Minsk, said: "There are massive problems going on… Now what we've heard as the latest is that Poroshenko is calling certain parts of the Russian position unacceptable, and that clearly shows you where the differences lie.
"They lie between Ukraine and Russia. We are also hearing that the Donetsk People's Republic representative and the Luhansk People's Republic representative, who are also in Minsk within a different location, have turned down whatever was planned, whatever was agreed here in the presidential palace."
The talks in the Belarusian capital were seen as a last opportunity for European leaders to save nearly bankrupt Ukraine from ever-widening defeats at the hands of rebels said by Kiev and the West to be armed by Russia.
Even as the deal was agreed, fighting over the last 24 hours in eastern Ukraine killed 10 civilians and two Ukrainian soldiers, Kiev and rebels said.
In another boost for Ukraine's beleaguered government, IMF chief Christine Lagarde said a deal had been reached on a new financial rescue plan worth $17.5bn.
In total, Ukraine will receive $40bn (35 billion euros) in assistance over four years coupled with bilateral loans from other sources, Lagarde said, helping to stabilise Kiev's finances after 10 months of conflict in the east.
Tense talks
The talks in Minsk went down to the wire, with Poroshenko emerging early on Thursday after 14 hours of negotiations to say the Kremlin was posing "unacceptable conditions".
"Unfortunately there's no good news yet," Poroshenko told AFP news agency during a break.
Details of the truce deal were not immediately released.
One of the main sticking points of the failed September version was who controls the 400km stretch of Russia's border with rebel-controlled Ukraine.
That sector is entirely under Russia and pro-Russian rebel control and is used, according to Kiev, as a conduit for separatist supplies - something the Kremlin denies.
There was also deep disagreement ahead of the Minsk talks over the size of the territory the rebels will control, given that they have made considerable gains in recent weeks, pushing back the outgunned Ukrainian army and volunteer units.
Moscow is also pushing for the separatist-held territories to be granted a large degree of autonomy, but Kiev only says that it is willing to decentralise some powers.
Poroshenko warned before the talks that he would introduce martial law throughout the country if they fail to stop the war.
Martial law would mark a significant escalation of the crisis, freeing up military resources for the fight in the east but also likely leading to the severance of foreign investment for cash-strapped Ukraine, including a vital IMF loan.
'One voice'
Poroshenko had said that he, Hollande and Merkel would speak "with one voice" to Putin, whom they accuse of backing the rebellion.
Poroshenko was scheduled to brief a European Union summit in Brussels on Thursday.
European Union foreign policy chief Federica Mogherini had said the talks would be a "turning point for good or bad".
US President Barack Obama, meanwhile, warned that a collapse in the peace process could push Washington into approving deliveries of weapons to Ukraine, a step many European leaders oppose for fear of getting drawn into open conflict with Russia.
The bloodletting in eastern Ukraine has been relentless in recent weeks as the rebels have pushed deeper into government-held territory and Kiev forces have counter-attacked.
As the leaders converged on Minsk, fighting raged on the ground with both sides trying to strengthen their hand at the negotiating table.
Insurgents have been battling for weeks to take the rail hub of Debaltseve, while Ukrainian forces on Tuesday captured ground around the port city of Mariupol.