Raids were conducted in Azizabad, Muhammadi Colony and Landhi areas where the paramilitary force nabbed eight suspects, said the Rangers spokesman.
He claimed that the suspects belonged to a militant wing of a group. Weapons were also seized from their possession.
The military’s crackdown in Karachi started late in 2013, when the murder rate soared and mutilated bodies were dumped in alleyways daily.
Police in Karachi are seen as too weak or corrupt to stamp out violence effectively, so many residents are willing to rely on the military.
The army has long accused a top political party of Karachi of racketeering, kidnappings for ransom and targeted killings in Karachi. Police recorded 2,507 murders in the city in 2013, up from 278 in 2006.