The EU should consider leaving the annexation of Crimea out of the debate over sanctions as part of a move to re-engage with Russia, according to a policy paper seen by AFP Thursday.

The paper drawn up by the office of the bloc's foreign policy chief Federica Mogherini ahead of talks between the 28-nation EU's foreign ministers next week proposes a new way forward to try end the nearly year-long standoff between Russia and the West over Ukraine.

Kazakh President Nursultan Nazarbayev and Ukrainian counterpart Petro Poroshenko agreed Thursday that the delayed talks on Ukraine conflict with leaders of Russia, France and Germany will take place at the end of the month, Kazakhstan said Thursday.

In a telephone call, the two leaders "noted that the meeting of leaders of Ukraine, Russia, Germany and France in Kazakhstan's capital Astana will happen at the end of January," the Kazakh presidency said in a statement.

It was a simple gesture of politeness that saved her: A young man offered her a seat on a bus transporting Ukrainians in search of pension payments in the war-torn east, but she remained standing.

"And today he is dead," Olga Kukunyuk, 31, said at a hospital in Volnovakha, where she was being treated for wounds to her arm and leg, before breaking down in tears. "If I had been seated in his place, I would be dead."

Russian Foreign Minister Sergei Lavrov warned Kiev on Wednesday against using force in the conflict in eastern Ukraine, where violence rose sharply this week.

"We are warning our Ukrainian colleagues against attempts to once again return to the scenario of force," Lavrov said at a press conference in Moscow.

The death toll from a stray rocket that hit a Ukrainian bus climbed to 12 on Wednesday as Moscow and Kiev traded blame for the separatist war's bloodiest incident since a September truce.

The long-range Grad rocket exploded on Tuesday near a commuter bus traveling towards the pro-Russian rebel stronghold of Donetsk from Ukraine's southeast coast.

The U.N. Security Council strongly condemned on Tuesday a rocket attack on a bus in east Ukraine that left 11 civilians dead.

In a unanimous statement of the 15 members including Russia, the council called for an investigation to bring those responsible for the attack to justice.

The United States will provide a $1 billion loan guarantee to embattled Ukraine if the government remains on track with an IMF-backed reform program, the Treasury Department said Tuesday.

The assistance would be part of the international effort to support Ukraine, whose economy has been ravaged by Russia's annexation of Crimea last year and continued fighting against pro-Russia insurgents in the country's industrial east.

Eleven Ukrainian civilians were killed and nearly 20 injured on Tuesday when a long-range Grad rocket apparently fired by pro-Russian insurgents hit an intercity bus in the separatist east.

Local police said the rocket appeared to have gone astray after being aimed by the gunmen at a checkpoint set up by government soldiers on the main highway connecting the rebel stronghold of Donetsk with Ukraine's southeastern coast on the Sea of Azov.

Three Ukrainian civilians and a soldier were reported killed on Tuesday in the latest wave of fighting across the country's separatist  east.

The Ukrainian military said another 10 soldiers were wounded in Grad rocket and mortar attacks by pro-Russian insurgents based around the eastern industrial city of Donetsk.

Russia has demanded an official explanation from France over its failure to deliver a Mistral-class warship due to concerns about Moscow's role in Ukraine, a military source said Tuesday. 

Moscow has written to France's overseas arms exporter in a move that could pave the way for legal claims against Paris, an unnamed official at Russia's Federal Service for Military-Technical Cooperation told state-run RIA Novosti news agency.