Subscription receipts, seven audiocassettes, a mobile phone set, a book, a flag and scores of leaflets and letters were also recovered from the residence.

The arrestees are madrassah Principal Moulana Shahidul Islam, 30, Abdul Gaffar, 23, Mahfuzzaman, 20, Tofazzel Hossain, 25, Masum Billah, 20, Mohammad Nizamuddin, 20, Bayezid, 25, Habibur Rahman, 30, Iqbal Hossain, 20, Afsaruddin, 22, Hafizur Rahman, 50, and Mizanur Rahman, 23 -- all from Faridpur.

Of the rest, Moulana Abdur Rouf, 39, hailed from Madaripur, while Khaled Saifullah, 19, Mohammad Moniruzzaman, 20, Lovelu Rahman, 22, Golam Rasul, age unknown, and Zillur Rahman, 20, hailed from Magura.

According to reports received in Dhaka, acting on a tip-off, Boalmari police raided the rented residence of upazila BNP Vice-president Kamruzzaman Mia alias Esken and made the arrests.

However, the BNP leader was not arrested.

Police said the arrestees confessed to coming to Faridpur from Jamia Islamia Nurul Ulum Kawmi Madrassah at Jibantala in Bhaluka upazila of Mymensingh to raise funds for an 'armed revolution' to resist the enemies of Islam.

A senior police official said they nabbed them when they were discussing formation of a 'militant group'.

Police showed them arrested under Section 54 of Criminal Procedure Code and produced them before court yesterday with a prayer to remand them for seven days.

Moulana Abdur Rouf is a teacher of the madrassah. He and the principal together came to the residence of Kamruzzaman and the 16 others joined them from different parts of the country later, police and local people said.

The subscription receipts were written in the name of Islami Shashantra Chhatra Andalan and the audio-cassettes had titles like Action, Jago Mujahid, Bir Mujahid and Hoonker. The flag had a red and green star and the book was in Arabic.

Earlier, the arrestees made religious deliberations at Andharkotha Jame Masjid at Boalmari Friday night and had dinner at Kamruzzaman's house, from where they were arrested. The BNP leader used to supply food to them, local people said.

Kamruzzaman's son Sohel, 24, a student of the madrassah, is absconding. He is allegedly linked to the extremist group.

Bhaluka police said a strong police squad was sent to the madrassah located in a remote hilly area.

Principal Shahidul Islam denied his involvement with any extremist group and said he came to Boalmari at the invitation of his student Sohel.