An explosion has ripped through a small hotel in the southern Philippines, killing three people and injuring at least 27 more. Reports said most of the casualties were at the hotel in the city of Zamboanga to celebrate a local wedding. The explosion blew the roof off the hotel and destroyed the upper levels, according to witnesses. Officials blamed the Abu Sayyaf group - a small Islamic militant organisation with links to al-Qaeda. Regional police director Felicisimo Khu said the blast had ripped through the second floor of Atilano Pension House at about 21:00 (13:00 GMT) on Sunday. Philippines map \"The bomb is composed of TNT component, we are looking the Abu Sayyaf terrorist group behind this explosion,\" Mr Khu was quoted as saying by the Philippines Star newspaper. The southern Philippines suffers from several overlapping conflicts. Abu Sayyaf is a small, extremely violent group which has launched several large-scale attacks in the past. They claim to be fighting to establish a separate Islamic state, but their influence has waned in recent years and their fighters are thought to number only a few hundred. The much larger Moro Islamic Liberation Front (MILF) has also carried out an armed struggle for independence from Manila. The MILF holds intermittent peace talks with the government and reached a ceasefire agreement in 2008. But the government launched a major offensive against renegade elements of the MILF in October.