Ukraine's border guards service says it has detained a Russian officer who was driving a truck packed with weapons including rocket-propelled grenades.
There was no immediate comment from the Russian military, but the self-styled defense ministry of the rebel forces in Donetsk said Sunday that the claim "provokes irony."
Ukraine and Western countries contend Russia is providing troops and weaponry to eastern Ukraine's rebels, who have been fighting Ukrainian forces since April 2014 in a war that has killed at least 6,400 people. Russia consistently denies the allegation.
The border guard service said the truck and its two occupants were intercepted late Saturday at a checkpoint about 30 kilometers (19 miles) south of Donetsk, the main rebel-held city. It said one of the men acknowledged he was a Russian major.
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