Leaders join Ukraine peace drive
French president Francois Hollande has said he is taking a new peace initiative to Ukraine alongside German chancellor Angela Merkel.
Speaking at a news conference in Paris and describing the Ukrainian conflict as a war, Mr Hollande said the pair will go to Kiev before arriving in Moscow on Friday with a proposal "based on the territorial integrity of Ukraine".
US secretary of state John Kerry is also in Ukraine to show support for the government amid a flurry of international diplomacy.
In a sign of the importance of the initiative and the urgency of the situation, this will be Ms Merkel's first trip to Moscow since the Ukrainian conflict broke out a year ago.
Mr Hollande said: "It will not be said that France and Germany together have not tried everything, undertaken everything, to preserve the peace."
Ms Merkel's spokesman, Steffen Seibert, said in a statement: "Given the escalation of violence in the past days, the chancellor and president Hollande are intensifying their months-long efforts for a peaceful settlement of the conflict in eastern Ukraine."
The surprise move came as the US edged toward offering Ukraine military aid.
Resurgent fighting in eastern Ukraine is threatening European security. France and Germany hope to could come up with a peace deal that both Ukraine and Russia can agree to.
In Brussels, Nato is preparing to boost its forces in response to Ukrainian unrest.
Fighting between Russia-backed separatists and government forces resumed in January after a month of relative calm, with more than 220 civilians killed in the past three weeks alone, according to the United Nations.
The UN has sharply criticised both sides for indiscriminate shelling and has called for a temporary truce.
At least three people were killed in overnight shelling in the rebel stronghold of Donetsk, local officials said, amid fierce fighting in several areas of eastern Ukraine.
In Moscow, Russian president Vladimir Putin's spokesman, Dmitry Peskov, said in a statement carried by Russian news agencies that Mr Putin, Ms Merkel and Mr Hollande will discuss "what the three nations can do to help put a quick end to a civil war in southeastern Ukraine, which has exacerbated in recent days with mounting casualties".
Mr Kerry came to Ukraine to show support for its embattled government as president Barack Obama's administration weighs up the possibility of sending arms to Kiev to help it fight Russian-backed separatists.
He brought 16.4 million dollars (£10.7 million) in new US humanitarian aid, but the Ukrainian government is anxious to use the visit to reiterate its plea for lethal aid.
Mr Obama has opposed the idea of sending weapons to Ukraine but sources in his administration say this position could change in the light of recent fighting.
Officials with Mr Kerry said he would discuss those needs with Ukrainian officials as well as new initiatives to resurrect a moribund ceasefire and resume a political dialogue to end the conflict.
Germany remains fiercely opposed to sending arms to Ukraine, a position that German foreign minister Frank-Walter Steinmeier reiterated.
Speaking after meeting with his Latvian counterpart, Edgars Rinkevics, in Riga, Mr Steinmeier said it would not improve the situation if "we now bring more weapons to the region".
"We believe that we must make another attempt to finally bring the violence to an end," he is quoted as saying.
In Brussels, Nato Secretary-General Jens Stoltenberg said the defence ministers meeting today are expected to approve boosting the size of the alliance's Response Force from 13,000 to 30,000, in reaction to Russian actions in Ukraine.
Russia has vehemently denied allegations of helping the rebels in Ukraine. The Kremlin acknowledged that Russian volunteers are fighting in eastern Ukraine but insists that Moscow has not sent its troops or weapons to help the rebels.
Russia has expressed concerned about Nato's build-up in eastern Europe while defending a heavy military presence at its border with Ukraine.
Mr Hollande appeared to be offering a nod to Mr Putin on one of his key demands: that Ukraine stays out of Nato.
Mr Hollande said: "France is not favourable to Ukraine's entry into Nato, let us be clear.
"We have to speak the truth to all the countries that are around us. For the Russians who are worried ... We have to settle this problem among Europeans. We are on the same continent."
An aide to Vladimir Putin praised Mr Hollande's comment, saying it reflects "a pragmatic approach, which the Kremlin welcomes".
Meanwhile, Ukrainian president Petro Poroshenko welcomed US secretary of state John Kerry to Kiev, calling it a "very critical moment in our history".
In a joint news conference after their talks, Mr Kerry urged Russia to show its commitment to a peaceful, diplomatic solution to the conflict in eastern Ukraine by ceasing its military support for the separatists and bringing them to the negotiation table.
"Our choice is diplomacy," Mr Kerry said, making no mention of providing Ukraine with military aid.
Mr Kerry sought to cast the new European initiative as part of unified western efforts to support Ukraine.
He said the visit to Kiev by Ms Merkel and Mr Hollande "underscores that, together, the United States, France, Germany and the rest of our international partners, stand united with Ukraine in calling on Russia to take the steps that I just outlined".
In Moscow, Putin adviser Yuri Ushakov said Russia was "ready for a constructive conversation" aimed at stabilising the situation, establishing a dialogue between the Ukrainian government and the rebels and rebuilding economic ties between eastern Ukraine and Kiev.
He said the Kremlin expects that the German and French leaders had taken Mr Putin's own peace proposals into account.
Western diplomats said Mr Putin gave Ms Merkel and Mr Hollande a nine-page peace plan, and added that the pair were taking a repackaged version of that with them.
The diplomats said the European version drops the most objectionable elements of the Russian plan and adapts it to fit what Ukraine and the Europeans want, such as some autonomy for eastern Ukraine with special protections for language, culture and local taxes.
Danish foreign minister Martin Lidegaard urged more sanctions against Russia to force the rebels back into peace talks, saying: "By throwing more weapons on the bonfire, I don't believe, unfortunately, that we will solve the problems in Ukraine."
European Union foreign ministers will be talking on Monday about increasing EU sanctions against Russia.
The top Nato commander, US Air Force Gen Philip Breedlove, said that Russia continues to supply the separatists with heavy, state-of-the-art weapons, air defences and fighters.
But Gen Breedlove also warned that any move to give Ukraine lethal defensive weapons must take into account a possible angry reaction from Russia.
"(That) could trigger a more strident reaction from Russia," he said.
Gen Breedlove emphasised the importance of making sure that Moscow and the separatists do not once again use a ceasefire to build up their forces and prepare for a new offensive to gain more territory.
Federica Mogherini, the EU's foreign policy chief, backed the French-German peace effort, saying "there is no military solution to the crisis in Ukraine".
Ukraine's economy, meanwhile, has been devastated by the crisis in the east.
Its currency, the hryvnia, slid 46% on Thursday against the US dollar, prompting the government to raise a key interest rate by a whopping 5.5 percentage points to 19.5%. The move has eased some pressure on the currency.
According to Mr Poroshenko, Ukraine is spending up to eight million dollars (£5.2 million) a day fighting the rebels.