Ansarullah Bangla Team (ABT) is a Bangladesh-based terror group affiliated with Al Qaeda.
The arrested person was identified as Gazi Rahman (35).
He was reportedly on the run.
His arrest was a part of Assam Special Task Force (STF)'s 'Operation Parghat'.
"Necessary legal action is being initiated in this matter. The STF continued its efforts to apprehend all individuals connected to this case," an official told NDTV.
At least 12 associates of the terror module have been arrested so far, officials said.