KIEV, June 10 - Pro-Russian separatists attacked Ukrainian military checkpoints and other strategic points in eastern Ukraine overnight but they were beaten off with only minor casualties on the Ukrainian side, Reuters reported Tuesday citing a government forces spokesman.

In a three-hour battle near the airport of Kramatorsk, rebels attacked the army with mortars but government forces returned fire, destroying their position and killing 40 "mercenaries", said the spokesman, Vladyslav Seleznyov.