Russian authorities on Wednesday arrested a group of Central Asian immigrants believed to be plotting a series of attacks on the Moscow area, Reuters reports.

The attacks were to be executed in early May, Russia's Federal Security Service said.

The development follows a series of reported terror threats against Europe. In April, ISIS terror cells were said to be plotting summer attacks on tourists at beach resorts across Europe by posing as drink vendors and placing bombs under sunbeds.

In March, ISIS claimed responsibility for rush-hour attacks in Brussels, which left 31 dead and more than 180 injured.