KIEV, Aug. 27 - Ukraine accused Russia of launching a new military incursion across its eastern border on Wednesday, as hopes quickly faded that Tuesday's talks between their two presidents might mark a turning point in a five-month-old crisis, Reuters reported.

Accusations of direct Russian support for pro-Russian separatists in Ukraine have prompted Western governments to impose sanctions on Moscow, despite its denials, and fanned tensions with NATO to levels not seen since the Cold War.

Ukrainian military spokesman Andriy Lysenko said a group of Russian soldiers had crossed the border in armored infantry carriers and a truck and entered the town of Amvrosiyivka, not far from where Ukraine detained 10 Russian soldiers on Monday.

Ukraine's Security Services also said in a statement it had detained another Russian soldier in the east of the country who has confessed his unit provided military support to separatist rebels.

Lysenko said fighting in two other towns, Horlivka and Ilovaysk, had killed about 200 pro-Russian rebels and destroyed tanks and missile systems. Thirteen Ukrainian service personnel had been killed in the past 24 hours and 36 had been wounded.

No comment was immediately available from the Russian defense ministry on the alleged incursion. Russia denies sending weapons and soldiers to help the rebels, and says the men captured on Monday had crossed an unmarked section of the border by mistake.

Late-night talks in the Belarusian capital Minsk had appeared to yield some progress towards ending a war in which more than 2,200 people have been killed, according to the U.N. -- a toll that excludes the 298 who died when a Malaysian airliner was shot down over rebel-held territory in July.

President Petro Poroshenko said he would work on an urgent 'road map' towards a ceasefire with the rebels. Russia's Vladimir Putin said it would be for Ukrainians to work out ceasefire terms, but Moscow would "contribute to create a situation of trust".

But Wednesday's new accusations from Ukraine made clear that the poisonous dispute over Russia's role remained unresolved.

In a telephone call with Putin, Germany's Angela Merkel said reports of a new Russian military incursion into Ukrainian territory had to be cleared up, a spokesman for the chancellor said in a statement.

"The latest reports of the presence of Russian soldiers on Ukrainian territory must be explained," said Merkel's spokesman Steffen Seibert. "She emphasized Russia's major responsibility for de-escalation and watching over its own frontiers."

A senior NATO diplomat said Russian support for the separatists was becoming increasingly open.

“I think there’s a shift here that we may be witnessing, very recently, from largely covert, ambiguous, deniable support to what appears increasingly to be flat-out, overt and obvious (support) and with the only form of ambiguity being that the Russians ... claim it is not happening,” said the diplomat, speaking to reporters in Brussels on condition of anonymity.

He said increasingly sophisticated weapons systems were now in the area, including the SA-22 surface-to-air missile, which is more advanced than the SA-11 system that many Western officials suspect rebels used to bring down the Malaysian jet. (rt/ez)