Tomi Soetjipto, Jakarta – A powerful bomb exploded at a boarding-house in the Indonesian capital Jakarta around dawn on Tuesday, seriously wounding five people, and police later found several unexploded devices in the building.

The blast destroyed much of the two-storey building in a south Jakarta suburb and also damaged nearby homes in the latest bomb explosion to hit the capital.

"It was a high explosive bomb but at this stage we are still investigating the type of bomb, whether it was homemade or not," Jakarta police spokesman Anton Bahrul Alam told Reuters. "We also found several unexploded bombs in a room next to the one where the exploded bomb was planted," Alam said.

The five wounded people have been taken to hospital. Alam said police had questioned 29 people, including residents of the boarding house, but they had yet to name any suspects. "We are hunting the tenant of the room where the bomb exploded. He is a student," Alam said.

A series of bomb blasts has rocked Jakarta and other cities across the troubled archipelago in the past year, adding to the problems facing the beleaguered administration of President Abdurrahman Wahid.

The spate of largely unresolved bomb blasts has underscored Indonesia's stumbling efforts to pull itself out of more than three years of crisis. Police often report finds of unexploded crude bombs and fake devices in public places.

Residents said Tuesday's explosion triggered panic in the usually quiet neighbourhood. One resident said he heard two blasts, although police have only reported one. "I was in a deep sleep when suddenly I heard two explosions and the roof tiles of my house fell near my bed. Straight away I ran out of the house with my grandchildren," neighbour Sumariyoto told Reuters.

Another neighbour, who gave her name as Ita, said about 20 students and workers lived in the boarding-house. "The explosion was very loud but we were too frightened to go out until the head of our neighbourhood association came out and shouted 'There's a bomb'. So we ran out and there was a lot of confusion," she said.

Two people were killed in Jakarta in May when a bomb destroyed a dormitory housing students from the restive province of Aceh. Police have said the dormitory might have been used as a makeshift bomb factory. Violence also hit Jakarta on Monday, when students clashed with police over sharp increases in fuel prices.