Brussels, Aug 29 (IANS): The NATO Thursday released some "satellite imagery" to show that "Russian combat forces engaged in military operations inside Ukraine".

Brigadier Gen. Nico Tak, director of the NATO Comprehensive Crisis and Operations Management Centre of Allied Command Operations in Mons, Belgium, said the images confirmed what NATO and its Allies had been seeing for weeks from other sources, Xinhua reported.

The source of the images is an independent firm named Digital Globe.

"Over the past two weeks we have noted a significant escalation in both the level and sophistication of Russia's military interference in Ukraine," Nico Tak said in the statement.

"The satellite images released provide additional evidence that Russian combat soldiers, equipped with sophisticated heavy weaponry, are operating inside Ukraine's sovereign territory," he added.

Russian government questioned claims in July that its forces fired artillery over the border into Ukrainian military positions.

Russia's state media said Russia's defence ministry has casted doubt on satellite images published by the US government, that Washington says back up its claim that Russia fired artillery into Ukraine.