(WASHINGTON POST) KIEV, Ukraine — Ukraine said Tuesday its forces detained a group of Russian paratroopers who crossed the border into eastern Ukraine, and the U.S. ambassador to Kiev warned of a possible “Russian-directed counteroffensive” by pro-Moscow separatists, raising tensions between the two countries ahead of a planned meeting between their presidents at a regional summit.

In a briefing Tuesday, Ukrainian military spokesman Andriy Lysenko said the Ukrainian army detained 10 Russian paratroopers in the Donetsk region, scene of some of the heaviest fighting with separatist rebels in the east.

The spokesman said the Russians were detained with their documents and weapons and had provided statements.

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