Minsk: The leaders of Ukraine, Russia, France and Germany were due to hold peace talks Wednesday aimed at halting a 10-month war in Ukraine where dozens were killed in the latest fighting.
The summit was the climax of a frantic diplomatic push to prevent the worst East-West crisis since the end of the Cold War from escalating, with US President Barack Obama warning President Vladimir Putin that Russia will be made to pay if the talks fail.
French President Francois Hollande and German Chancellor Angela Merkel, the driving forces behind the peace effort, will "try everything" to make it work, a French presidential source said, with "quite a lot of problems still to be resolved," just hours ahead of the summit expected to start early evening in Minsk.
The bloodletting on both sides has been relentless in recent weeks as pro-Russian separatists have pushed a new offensive and Kiev forces have counter attacked.
At least 46 people were killed in the last 24 hours, including 16 in a devastating rocket attack on Kramatorsk, the Ukrainian government`s eastern military headquarters and administrative hub.
In the rebel stronghold of Donetsk, city officials said that eight people had been killed, including six in a mortar strike on the city early Wednesday.
Rebels, who rarely announce military casualties, said they had lost seven fighters.
In Minsk, Ukrainian President Petro Poroshenko is to come face-to-face with Russian strongman Vladimir Putin -- who Kiev and its Western allies accuse of masterminding the pro-Russian rebellion -- for the first time since October.
Poroshenko, who was scheduled to join a European Union summit in Brussels on Thursday to discuss the conflict, described the Minsk meeting as "one of the last chances to declare an unconditional ceasefire and withdraw heavy artillery."
If the talks fail, Obama has warned that Washington may decide to start providing lethal weapons to Ukraine, a step many European leaders oppose for fear of getting drawn into open conflict with Russia.
On Tuesday, Obama spoke to Putin by phone and sought to pressure him to rein in the rebels, who have close political links to Moscow, and embrace the chance for peace.
"If Russia continues its aggressive actions in Ukraine, including by sending troops, weapons, and financing to support the separatists, the costs for Russia will rise," the White House said.
Western diplomats, however, warn that the warring sides remain deadlocked over key issues, and that there is no guarantee of reaching a conclusive accord.
"Nothing is certain yet, and holding a summit does not mean it will lead to success," German Foreign Minister Frank-Walter Steinmeier said. The plan to be discussed is based largely on repeatedly broken peace deal between Kiev and the rebels in September. The hope is that, at minimum, a ceasefire to halt fighting that has killed hundreds of civilians in recent weeks can be agreed upon in Minsk.
In lower-level talks in the city on Tuesday ahead of the summit, the separatists submitted their settlement proposals but warned that "it is too soon to speak about a ceasefire".
A key sticking point is whether a new deal will extend rebel control over some 500-square kilometres (200-square miles) of territory seized over the past month.
As leaders converged on Minsk, fighting raged on the ground with both sides trying to strengthen their hand at the negotiating table.
Insurgent fighters 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.
Kiev is desperate to get Putin -- who has watched Western sanctions and low oil prices batter the Russian economy -- to put his signature on a deal. But the former KGB spy has consistently told Ukraine`s government it needs to reach an agreement with the rebels, not with him.
Moscow is pushing for the separatist-held territories to be granted a large degree of autonomy, while Ukraine is demanding it get control back over some 400 kilometres (250 miles) of its border with Russia.
Kiev and the West accuse Putin of pouring soldiers and troops into Ukraine to spearhead the insurgency, but Moscow denies it is behind the fighting.