About 400 elite mercenaries from the notorious US private security firm Academi (formerly Blackwater) are taking part in the Ukrainian military operation against anti-government protesters in southeastern regions of the country, German media reports.

The Bild am Sonntag newspaper, citing a source in intelligence circles, wrote Sunday that Academi employees are involved in the Kiev military crackdown on pro-autonomy activists in near the town of Slavyansk, in the Donetsk region.

On April 29, German Intelligence Service (BND) informed Chancellor Angela Merkel’s government about the mercenaries’ participation in the operation, the paper said, RIA Novosti reported. It is not clear who commands the private military contractors and pays for their services, however.

In March, media reports appeared suggesting that the coup-imposed government in Kiev could have employed up to 300 mercenaries.That was before the new government launched a military operation against anti-Maidan activists, or “terrorists” as Kiev put it, in southeast Ukraine.

At the time, the Russian Foreign Ministry said then that reports claiming Kiev was planning to involve “involve staff from foreign military companies to ‘ensure the rule of law,’” could suggest that it wanted “to suppress civil protests and dissatisfaction.”

In particular, Greystone Limited, which is currently registered in Barbados and is a part of Academi Corporation, is a candidate for such a gendarme role. It is a similar and probably an affiliated structure of the Blackwater private army, whose staff have been accused of cruel and systematic violations of human rights in various trouble spots on many occasions.

“Among the candidates for the role of gendarme is the Barbados-registered company Greystone Limited, which is integrated with the Academi corporation,” the Foreign Ministry said in a statement. “It is an analogue, and, probably and affiliated body of the Blackwater private army, whose employees have repeatedly been accused of committing grievous and systematic human rights abuses in different troubled regions.”

Allegations increased further after unverified videos appeared on YouTube of unidentified armed men in the streets of Donetsk, the capital of the country’s industrial and coalmining region. In those videos, onlookers can be heard shouting “Mercenaries!”“Blackwater!,” and “Who are you going to shoot at?”

Academi denied its involvement in Ukraine, claiming on its website that “rumors” were posted by “some irresponsible bloggers and online reporters.”

“Such unfounded statements combined with the lack of factual reporting to support them and the lack of context about the company, are nothing more than sensationalistic efforts to create hysteria and headlines in times of genuine crisis,” the US firm stated.

The American security company Blackwater gained worldwide notoriety for the substantial role it played in the Iraq war as a contractor for the US government. In recent years it has changed its name twice – in 2009 it was renamed Xe Services and in 2011 it got its current name, Academi.

The firm became infamous for the alleged September 16, 2007 killing of 17 Iraqi civilians in Baghdad. The attack, which saw 20 others wounded, was allegedly without justification and in violation of deadly-force rules that pertained to American security contractors in Iraq at the time. Between 2005 and September 2007, Blackwater security guards were involved in at least 195 shooting incidents in Iraq and fired first in 163 of those cases, a Congressional report said at the time.