The al-Nusra Front is a leading al-Qaeda affiliate and has been used as cover for its violent operations across the world.
Samiul Rahman aka Ibn Hamdan was nabbed from the capital's Kamalapur area on Monday morning, Dhaka Metropolitan Police (DMP) Deputy Commissioner Md Masudur Rahman said.
“We have found out that he was trying to set up contact with IS and al-Nusra Front.”
A press briefing will be held at DMP Media Center at 11:30am.
Earlier, the Detective Branch had said a British citizen has been working to strengthen al-Qaeda’s network in Bangladesh after arresting two Ansarullah Bangla Team activists on Thursday.
The detectives said the two were trying to join IS fighting in Syria.
It is not clear whether Samiul Rahman's arrest follows the interrogation of the two Ansarullah Bangla Team activists.