A bomb exploded at a Moscow apartment complex, authorities said, killing and wounding several people, including the founder of a battalion fighting alongside Russian forces in Ukraine.
The February 3 incident was the latest in a string of unusual explosions and shootings, which have raised fears of a return to the gangland violence that plagued the Russian capital in the 1990s.
Russian authorities were quoted by the state news agency TASS as saying that the device detonated around 9:45 a.m. local time and may have been delivered to the Alye Parusa complex by courier.
Among the casualties was Armen Sarkisian, the founder of an ethnic Armenian military unit that has been fighting in Ukraine alongside Russian troops. The Interfax and TASS quoted unnamed officials as saying he died after being hospitalized in critical condition.
Eyewitnesses said that at the time of the explosion Sarkisian was seen walking down a hall in the building toward a parking lot.
TASS quoted an unnamed law enforcement official saying it was likely an intentional act. There was no immediate claim of responsibility.
The newspaper Kommersant said Sarkisian's bodyguard, Oleg Kasperovich, was killed and another bodyguard seriously injured.
The unit Sarkisian is credited with founding is called ArBat, now formally a part of Redut, a Russian military intelligence-backed mercenary network.
SEE ALSO: How Russia's GRU Set Up A Fake Private Military Company For Its War In UkraineUkrainian authorities have accused him of involvement in the violence during the 2014 Maidan street protests in Kyiv.
According to Ukrainian media, he is also a close acquaintance of former Ukrainian President Viktor Yanukovych, who fled to Russia following the Maidan protests.
In April 2018, Sarkisian was detained in France, where he was awaiting extradition to Ukraine. However, he was released after two days "on personal recognizance."
The bombing occurred just over a month after a top general in Russia's chemical and biological weapons protection forces was killed when an electric scooter detonated on the sidewalk outside his building.