Ukrainian security services have released video footage purporting to show Russian servicemen who were captured by Ukrainian government forces while fighting alongside pro-Moscow rebels in Ukraine.

The footage, which is likely to fuel allegations from Kiev and its Western allies of Russian involvement in the war, appeared on the day the Russian and Ukrainian leaders are to meet for talks in the Belarussian capital to try to end the conflict.

Russia denies giving military help to the separatist rebellion in eastern Ukraine. Its defence minister was quoted as saying this morning that they had crossed the border by mistake.

Ukraine's state security service said  it had detained 10 Russian paratroopers who had crossed into Ukrainian territory from Russia in a column of several dozen armed infantry vehicles.

In footage posted on the official Facebook page of the Ukrainian government's "anti-terrorist operation," the men were shown dressed in camouflage fatigues.

One of them, who identified himself as Ivan Milchakov, listed his personal details, including the name of the paratroop regiment he said is based in the Russian town of Kostroma.

"I did not see where we crossed the border. They just told us we were going on a 70-kilometre march over three days," he said.

"Everything is different here, not like they show it on television. We've come as cannon fodder," he said in the video.

Another man in the footage, who gave his name as Sergeant Andrei Generalov, said: "Stop sending in our boys. Why? This is not our war. And if we weren't here, none of this would have happened. They would have sorted things out with the government themselves."

The Russian servicemen were detained with their personal documents and weapons, near the small town of Amvrosiyivka in Donetsk region, the Ukrainian state security service said.

"Officially they are on military exercises in various corners of Russia. In reality they are involved in military aggression against Ukraine," Defence Minister Valeriy Heletey said in a Facebook post.

Russian Foreign Minister Sergei Lavrov on Monday dismissed reports of a Russian incursion into Ukraine, saying it was "dis-information" by the authorities in Kiev.