Five detainees who took the employees hostage have claimed that they are supporters of the Islamic State and have demanded a car and free passage.
Russia’s RIA state news agency reported, citing unidentified sources, that the detainees who are involved in taking the employees hostage are accused of terrorism.
Meanwhile, negotiations on the release of the hostages are reportedly under way.
“The institution operates as usual, the situation is under control,” the service said in message on the Telegram messaging app on Sunday. According to reports, road traffic around the centre has been limited.
Baza, a Telegram channel with links to Russian law enforcement, said that six of detainees were involved in taking the employees hostage, among them several already convicted of terrorism charges.
However, the Reuters did not independently verify the Baza report.