The area was reportedly the headquarters of the All Tripura Tiger Force (ATTF).
Around 200 high explosive anti-tank weapons with as many chargers were recovered in a daylong drive in the Satchharhi hill by the RAB, bdnews24.com quoted RAB's Additional Director General (operations) Ziaul Ahsan as saying Tuesday.
The recovery has been pegged as the single biggest case of arms seizure since the 2004 Chittagong arms case in the country.
Around 100 RAB personnel conducted the raid at the 100-foot hillock and found 184 high explosive anti-tank weapons and 154 chargers inside bunkers dug in deep holes in the hillock.
Ahsan said there was a possibility of recovering more arms.
Meanwhile, an investigation has been launched to ascertain the source of the ammunition.
The All Tripura Tiger Force (ATTF) is a militant group from the Tripura region with its chief Ranjit Debbarma standing trial in his home state Tripura on countless charges of murder and abduction.
Debbarma, who is said to have been handed over to India by Bangladesh after being arrested in Jan 2013, is very close to United Liberation Front of Assam (ULFA) military wing chief Paresh Barua.
The ULFA and ATTF have been involved in smuggling Chinese-made weapons through south-east Asia and taking them to rebel bases like Satchharhi, from where they would be smuggled into India's troubled northeast, the report said.