MOSCOW — About 300 US Army paratroopers on Friday arrived in Ukraine for training exercises with national guard units, a move criticized by Moscow and eastern Ukraine’s Russia-backed separatist rebels.

The troops, from the Italy-based 173rd Airborne Brigade, are to spend several weeks training a total of about 900 Ukrainian national guardsmen.

Russian Foreign Ministry spokesman Alexander Lukashevich denounced the guardsmen as “ultranationalists … who stained themselves with the blood of women, children and the elderly during their punitive operations.”

Although Interior Minister Arsen Avakov had said the guardsman units could include the Azov Battalion, a far-right formation notorious for using an insignia used by many military units in Nazi Germany, U.S. Embassy spokesman James Hallock said Azov fighters would not be among those trained.

Though fighting has diminished substantially since a February cease-fire deal was signed in Minsk, Belarus, clashes continue and each side accuses the other of wanting to resume the conflict. Lukashevich said the U.S. troops’ presence violates the section of the Minsk agreement that bans foreign “armed formations” from Ukraine.

On Friday, the UN Human Rights Commissioner’s office said at least 6,116 people have been killed since the fighting broke out a year ago.

National guard units, many of which began as volunteer groupings, have been an important part of Ukrainian forces’ fighting against the separatists. Two national guard units, working on weeklong rotations, are holding the town of Shyrokyne, currently the most fraught location in the east. Shyrokyne is just east of the major port city of Mariupol, which Ukraine fears rebels aim to seize to establish a land corridor between the Russian mainland and the Russia-annexed Crimean peninsula.

Dmitry Peskov, the spokesman for Russian President Vladimir Putin, also criticized the American move.

“The participation of instructors and specialists from a third country on the territory of Ukraine, where an unresolved intra-Ukrainian conflict remains, where problems persist in carrying out the Minsk agreement, is far from helping resolve the conflict. To the contrary, it enables destabilizing the situation,” Peskov said.

Rebel envoy Denis Pushilin said the exercises were “a self-evident escalation.”