The men are allegedly members of the revived Jama'atul Mujahideen Bangladesh (JMB).
"They are part of a cell headed by Oliuzzaman aka Oli. The cell's 10 to 12 members are all residents of Kafrul and Mirpur," said RAB Additional Director General Anwar Latif Khan.
"These men have been in the same group for more than a year. They have been recently planning attacks on government structures."
The RAB officer said they were looking for two more suspects, 'Monir' and Salman aka Abdullah, who have been tasked with carrying out these plans.
The JMB cell's alleged head, Oliuzzaman, were among the five captured by the elite police unit. He is a former electrical engineering student from Bangladesh University of Engineering and Technology (BUET).
The rest are - Anwarul Alam, Abul Kashem, Saleh Ahmmed Shish and Md Mohan aka Mohsin. Anwarul is also a former student from BUET.
The five have been named in a terrorism case at Kotwali Police Station. They were sent to prison after a court denied them bail.
RAB received information that members of the JMB faction loyal to 'Sarwar-Tamim' were planning attacks while in hiding.
Oliuzzaman and Anwar were detained from Badda area. The information they divulged led to the others' arrest, said the RAB official.
"They have admitted to taking part in militant activities during primary questioning."