Russia's Foreign Minister Sergei Lavrov has said the talks on Ukraine crisis taking place in the Belarusian capital, Minsk, should seek an immediate ceasefire in the conflict.

The statement came on Monday ahead of the Ukraine "contact group" talks that includes representatives from Russia, Ukraine, the Vienna-based OSCE security and rights organisation and separatist rebels in eastern Ukraine.

I very much count on today's negotiations being devoted above all to the task of agreeing an immediate ceasefire, without conditions. Sergei Lavrov, Russian FM

Lavrov said that the Ukrainian forces must pull back from positions from which they can hit civilian targets.

"They must leave positions from which they can harm the civilian population," Lavrov told students in Moscow.

"I very much count on today's negotiations being devoted above all to the task of agreeing an immediate ceasefire, without conditions."

Russian President Vladimir Putin raised the stakes in the conflict on Sunday by calling for the first time for statehood to be discussed for the restive east of the former Soviet state.

"We need to immediately begin substantive talks... on questions of the political organisation of society and statehood in southeastern Ukraine," the Russian leader said in an interview with Channel 1 state television.

However, Putin's spokesman Dmitry Peskov said there was no new endorsement from Moscow for rebel independence. Asked if "New Russia", a term pro-Moscow rebels use for their territory, should still be part of Ukraine, Peskov said: "Of course."

"Only Ukraine can reach an agreement with New Russia, taking into account the interests of New Russia, and this is the only way to reach a political settlement," he added.

Moscow has previously only called for "federalisation" that would grant greater rights to the eastern regions of Ukraine, where predominantly Russian speakers live.

Past talks by the "contact group" have covered technical issues such as access to the crash site of a Malaysian airliner shot down in July, but not political questions. Kiev rejects direct talks with the rebels.

Struggle for key airport

Ukraine's military said on Monday that its forces were battling a Russian tank battalion for control of a vital airport in the east of the country.

Fighting continued to rage near Luhansk, the region's other main city, for control of the main civilian airport just to its south, the military said in a statement.

"Ukrainian paratroopers are fighting a tank battalion of the Russian armed forces to hold the airport," it said.

In the past 24 hours, the separatists had lost 80 fighters, some armoured vehicles and a missile system, the military said, giving no figures for Ukrainian losses.

In a statement on Monday, President Petro Poroshenko accused Moscow of "direct and open aggression" against his country.

Poroshenko, speaking at a military academy in Kiev, said Russia's direct involvement in the war against the separatists in eastern Ukraine had tipped the balance on the battlefield and was the main reason for recent reversals.

The past week has seen Ukrainian forces flee in the path of a new rebel advance, drawing concern from Ukraine's Western allies, who say armoured columns of Russian troops came to the aid of a rebellion that would otherwise have been near collapse.

Meanwhile, the EU leaders agreed on Saturday to draw up new economic sanctions against Moscow. The US and EU have gradually tightened economic sanctions against Russia, first imposed after Moscow annexed Crimea following the ousting of Kiev's pro-Russian president by protesters in February.