Ahmed alias Tahir was arrested in Islamabad and eight kilograms of explosives were seized from him, Inspector General of Police Kaleem Imam told mediapersons.
Imam said Ahmed had links to radical Lal Masjid and had also fought in the troubled Swat valley. A suicide jacket reportedly found in his possession was shown to the media.
Ahmed was allegedly linked to at least four recent suicide attacks, including one on the office of the World Food Programme on October 5 that killed five persons, including an Iraqi national and two Pakistani women.
Police obtained vital clues about elements involved in recent attacks on senior army officers in Islamabad by questioning Ahmed, Imam said.
A brigadier and his driver were killed and another brigadier was injured in these attacks. Ahmed, a youth in his twenties sporting a long beard and closely cropped hair, told mediapersons he was recruited from the tribal areas. He claimed the militants used money paid as ransom for kidnapped persons to fund their activities.