Police in the Indonesian province of Papua say the accidental discovery of a cache of illegal explosives has led to fears of covert militia activity in the region. Police say tribal leaders in the coastal town of Sorong, where police have arrested a local businessman and Islamic politician, have raised the concerns.

Sorong's district police chief Faisal Abdul Nasir said businessman Mohammed Koya faces up to 20 years in jail for allegedly storing 12 homemade bombs in the warehouse of his cargo handling company. Mr Koya is quoted as saying he stored the explosives for self-protection.

His lawyer denied he was involved with any extremist groups that have established a presence in Sorong and other coastal towns of Papua in recent years.