Authorities in St.

Petersburg have been deporting migrants en masse in the week since the deadly attack on a Moscow region concert hall, the legal rights group Perviy Otdel said Friday.More than 64 foreigners were deported from the city’s Vyborgsky district on Thursday alone, the NGO said, citing one of its unidentified lawyers.“Temporary detention centers for foreign citizens are packed, surrounded by special vehicles and buses heading to the airport,” the lawyer was quoted as saying.A number of buses carrying migrants were also headed to St.

Petersburg’s Pulkovo International Airport on Friday afternoon, they added.The countries where the migrants were being sent to were not specified, though it is known that labor migrants in Russia mostly hail from poor Central Asian countries.Bailiffs reportedly refer to St.

Petersburg’s mass deportations as “Operation Anti-Migrant,” with raids targeting local hostels and apartments.

Similar raids were reported in Moscow and other Russian cities.Anti-immigrant sentiment surged after four gunmen — who were later identified as Tajik nationals — stormed Crocus City Hall last Friday, killing 144 people and injuring 382 in the shooting and massive fire at the popular concert venue.Four other suspects placed in pre-trial detention this week are also originally from Tajikistan.

A ninth suspected accomplice is from neighboring Kyrgyzstan.Islamic State affiliate ISIS-K has claimed responsibility for the massacre.

Russia has blamed radical Islamists, Ukraine and its Western allies for the deadliest attack in Russia since the 2004 Beslan school siege.