KIEV claimed today that its forces had captured 10 Russian soldiers in an eastern Ukrainian region where troops are locked in heavy fighting with pro-Russia separatists.

The anti-rebel operation command, which includes the military, the national guard and right-wing militias, claimed the soldiers hailed from a Russian paratrooper division and were captured on Monday in the area of Amvrosiivka, near the border in the Donetsk region.

However, the Russian Defence Ministry denied any deliberate intervention and said the soldiers had been patrolling the border and crossed the frontier inadvertently.

“The soldiers crossed by accident on an unmarked section and, as far as we understand, showed no resistance to the armed forces of Ukraine when they were detained,” the ministry said.

Meanwhile, smoke rose from outside the city of Novoazovsk in Ukraine’s far south-east after what residents said had been a heavy artillery barrage.

Novoazovsk lies on the Azov Sea on the road that runs from Russia to the Ukrainian port of Mariupol.

It was the second day attacks had been reported in the vicinity of Novoazovsk, which is in eastern Ukraine’s separatist Donetsk region but had previously seen little fighting.

Ukrainian officials claimed that artillery had been fired from the Russian side of the border.

However, Russia has denied allegations from Nato that it had fired artillery into Ukraine to help the rebels.

The shelling came on the same day that Ukrainian President Petro Poroshenko dissolved the Kiev parliament and called early elections.