It said on Monday that the arrests were made during raids at the capital's Uttara and Kalabagan.
Officials said they belonged to the 'Tamim-Sarwar group' of the outfit, which has been blamed for several recent terror attacks, including the Gulshan cafe attack.
Details will be provided at a media conference later on Monday, said the elite police unit.
According to RAB, Sarwar used the alias ‘Shayokh Abu Ibrahim Al Hanif’ and formed the Neo-JMB.
He was a leader of the banned Jama’atul Mujahideen Bangladesh (JMB), from which the ‘Neo-JMB’ originated.
On Aug 27, three persons, including Canadian-Bangladeshi Tamim Ahmed Chowdhury, were trapped in a hideout in Narayanganj’s Paikparha during a raid by the counterterrorism unit.
Tamim was one of the key operatives of Neo JMB and he was killed in action when he refused to surrender, police had said.