A unspecific number of US paratroopers has arrived in Ukraine's western Lvov region to train Ukrainian soldiers, US Ambassador to Ukraine Geoffrey Pyatt said Friday.

"The paratroopers from the US 173rd Airborne Brigade arrived in Ukraine to train Ukrainian troops," Pyatt wrote on his official Twitter account, without disclosing the specific number of the troops and the period of their deployment.

But Ukrainian Interior Minister Arsen Avakov said last month that some 900 Ukrainian military servicemen will be trained at the Yavoriv military facility by 290 American paratroopers under the so-called Fearless Guardian framework.

According to Avakov, the training will be held in three phases, each lasting eight weeks, and will involve servicemen from the National Guard of Ukraine -- the volunteer battalions which fight pro-independence insurgents in eastern regions.

The Yavoriv military facility is near the Polish border and nearly 1,000 km away from the combat area in eastern part of the country.

The move to deploy US military instructors in Ukraine has irked the Kremlin, which said the US military presence could destabilize the country.