PARIS, France (AFP) — US Secretary of State John Kerry and his Russian counterpart yesterday huddled once again for tough talks trying to resolve the Ukraine crisis, as Moscow urged Kiev to become a neutral, federal state.

The latest bid to resolve the worst East-West stand-off in the post-Cold War era comes after Russian leader Vladimir Putin unexpectedly called US President Barack Obama on Friday asking to pursue a diplomatic solution.

Washington and its allies have imposed a slew of stinging sanctions on Moscow after it annexed Crimea and massed thousands of troops on the borders of eastern Ukraine.

The two men met in the lavish residence of the Russian ambassador to France seeking to hammer out a plan to end the crisis sparked after the pro-Kremlin regime in Kiev fell in February.

Despite the massive troop build-up on Ukraine’s borders, Lavrov has insisted Moscow had “absolutely no intention and no interests in crossing the Ukrainian border”.

But he called on Western powers to back a proposal for Ukraine’s Russian-speaking regions to have greater powers in a “federal” and neutral Ukraine.

“If our Western partners are ready, then Russia, the United States and the European Union could form a support group on Ukraine,” Lavrov told Russian state television.

This would lead to talks between “all Ukrainian political forces without exception, naturally excluding armed radicals”, and would end in a new constitution allowing for a “federal structure” with greater regional autonomy, he said.

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.

And flashmobs took to seven Ukrainian airports yesterday, with orchestras and choristers performing Beethoven’s Ode to Joy, also the European anthem, in tribute to the 100 people killed in the weeks-long uprising which ousted president Viktor Yanukovych and his pro-Moscow government.

Thousands of mourners 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.

A plan outlining how the crisis could be resolved has gone through a number of modifications.

And Kerry and Lavrov, who have already met at least four times, agreed to have dinner yesterday to continue discussions after talking for almost three hours.

At the heart of the US initiative is a commitment by Russia to halt its military build-up near its ex-Soviet neighbour — estimated by US and EU diplomats to have reached between 30,000 and 40,000 soldiers in recent days — and to order its Crimean forces back to their bases.

Moscow has, however, so far rejected direct talks with the new, interim Kiev leaders under the auspices of either Washington or some international contact group.

Russia further wants the 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.