File Photo: Police and other law enforcement officers stand in an intersection near the shootout scene in Moscow. AFP
Moscow Mayor Sergei Sobyanin said on Twitter that a suspect was detained. Sobyanin didn't offer any details about the assailant or his possible motive, saying only that the incident took place in the southeast of the city.
"Doctors are doing all they can to help those wounded,'' the mayor said.
State news agency Tass reported, citing an unidentified law enforcement source, that the man drew out a gun and started firing shots after an argument with a security guard who asked him to put on a face mask, which is mandatory in such facilities.
Tass also quoted witnesses of the incident as saying that a girl aged 10 or 11 was among the people wounded.