Russian President Vladimir Putin has raised the stakes in the Ukraine conflict by calling for the first time for statehood to be discussed for the restive east of the former Soviet state.
Putin's remarks came on Sunday just hours after the European Union gave Moscow - which the bloc accuses of direct involvement in the crisis - a week to change course or face new sanctions.
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"We need to immediately begin substantive talks... on questions of the political organisation of society and statehood in southeastern Ukraine," the Russian leader was quoted by Russian news agencies as saying.
Moscow has previously only called for "federalisation" that would grant greater rights to the eastern regions of Ukraine, where predominantly Russian speakers live.
But Putin had long sparked speculation that he may be seeking to create a pro-Russian statelet when he began to employ the loaded Tsarist-era term "Novorossiya", or New Russia, to refer to several regions in southeast Ukraine.
His spokesman, Dmitry Peskov, said on Sunday that the Russian leader was not talking about "Novorossiya's" independence from Ukraine but "inclusive talks".
"Only Ukraine can agree with Novorossiya," he was quoted as saying.
Putin's tough talk comes as rebels have begun to reject the concept of "federalisation" in recent weeks, calling for independence from Kiev, as they turned the tide on advancing Ukrainian troops by snatching a series of towns.
Kiev has warned that it is on the brink of "full-scale war" with Moscow which Europe fears would put the continent at risk of conflict.
The EU agreed to take "further significant steps" if Moscow did not stop its support for the rebels, with new sanctions to be drawn up within a week.
Earlier on Sunday, Ukraine handed over a group of captured Russian paratroops and Russia returned 63 Ukrainian soldiers who crossed into its territory last week, Russian news agencies quoted a paratroop commander as saying.
RIA news agency quoted Russian Major-General Alexei Ragozin as saying the paratroops had been handed back after "very difficult" negotiations.
Ukraine said last week it had captured 10 paratroops and presented them to the press as evidence that the Russian military is fighting alongside pro-Moscow separatist rebels in eastern Ukraine.
Russia said the men had crossed an unmarked section of the border by accident.