The United States and Russia failed Sunday to reach a breakthough deal on Ukraine as US Secretary of State John Kerry called on Moscow to pull back its forces saying they were creating a "climate of fear."
But the two sides did agree to keep talking after what were described as "frank" and "constructive" negotiations lasting some four hours late into the night at the lavish residence of the Russian ambassador to Paris.
The latest bid to resolve the worst East-West standoff in the post-Cold War era came after Russian leader Vladimir Putin unexpectedly called US President Barack Obama on Friday.
Both sides stressed they believe in finding a diplomatic solution and put forward plans on how to end the crisis, triggered in February when the pro-Moscow government in Kiev fell and the Kremlin sent thousands of troops into Crimea before annexing the southern peninsula.
Washington and its allies have imposed stinging sanctions on Moscow for its flagrant land grab and for massing thousands of troops on the borders of eastern Ukraine. US officials believe that the measures are biting hard and causing Putin to seek a way out.
Russian Foreign Minister Sergei Lavrov said the hastily-arranged talks with Kerry in Paris had been "constructive" and would continue, but he reiterated Russia's belief that Ukraine should become a federal nation, according its ethnic Russians greater autonomy.
Kerry said Washington had agreed to study Moscow's ideas unveiled in the "frank" talks, but stressed the US administration believes Russia's "actions to be illegal and illegitimate."
He urged Russia to pull back its forces from the borders of Ukraine, and said any talks on the country's future must include Kiev's leaders.
"We will not accept a path forward where the legitimate government of Ukraine is not at the table. This principle is clear. No decisions about Ukraine without Ukraine," Kerry told reporters later.
Any progress "must include a pullback of the very large Russian force that is currently massing along Ukraine's borders," Kerry added, saying the US believed "these forces are creating a climate of fear and intimidation in Ukraine" which did not create the right atmosphere for talks.
But Lavrov did not mention the troops in his press conference, and both sides acknowledged differences still remained.
Protecting Russian minorities
Washington would work with the new interim leaders in Kiev to ensure the rights of minorities and language rights, as well as the disarmament of militias and free and fair presidential elections in May, Kerry said, in a tacit acknowledgement of some of Moscow's concerns.
Moscow's plan would allow parts of Ukraine, a former Soviet republic, to declare Russian as a second official language and secure more independence from Kiev -- a move analysts view as a bid to weaken the authority of what is likely to be a permanent new pro-Western leadership.
"We are convinced that federalism is a very important element of the constitutional reforms," Lavrov said. "We have to find a consensus, a compromise between the regions of Ukraine."
However, Kerry did not win a Russian commitment to halt its military build-up near its ex-Soviet neighbour and to order its Crimean forces back to their bases.
The US perception is that Moscow's troops, estimated at some 30,000 to 50,000 around Ukraine's borders, have been put in place not simply to intimidate Ukraine but also to be used as a bargaining chip towards some kind of endgame.
Flashmobs took to seven Ukrainian airports Sunday, with orchestras and choir singers performing Beethoven's "Ode to Joy", also the European anthem, in tribute to the 100 people killed in the weeks-long uprising that ousted president Viktor Yanukovych and his pro-Moscow government.
Thousands of mourners on Sunday also visited Kiev's Independence Square, the heart of the protest movement, many shedding tears as they laid fresh flowers around makeshift shrines and barricades perfectly preserved since the street battles ended.
"I want my children to know what we went through and to remember these people who gave their lives for their future," said Volodymyr, a computer engineer visiting the site with his two children.
Moscow has also so far rejected direct talks with the new, interim Kiev leaders which Kerry again called for, insisting the US was working with the new interim leaders to "support the people of Ukraine's right to choose their own future."
"I will say that at least tonight Foreign Minister Lavrov indicated that Russia wants to respect the right of Ukrainians to make that choice," the top US diplomat said.
Russia also wants a new constitution to proclaim Ukraine a neutral country that will never join forces with NATO -- membership which Kiev's interim leaders say they are not seeking now.