BANDA ACEH, Jan 1: A bomb killed nine people, including a baby, and injured more than 20 at an open-air new year celebration where hundreds had gathered in Indonesia's troubled Aceh province, officials said on Thursday.

The Aceh martial law administration, which has ruled the region since talks between the government and the separatist Free Aceh Movement (GAM) collapsed in May, blamed the rebels for the blast. The GAM, which has fought for independence for the gas-rich province since 1976, could not be reached for comment.

"The perpetrators clearly come from GAM. But we also regret that the event organizers did not adequately cooperate with the military which could have provided proper security for the show," Aceh military chief Major General Endang Suwarya told reporters.

The spectators had gathered in a public field near a night market for a fiesta on Wednesday in the town of Peureulak, 1,600kms northwest of Jakarta, when the bomb, planted near the stage, exploded.

"Nine civilians died and more than 20 suffered heavy injuries after the blast," Lieutenant Colonel Ahmad Yani Basuki, an Aceh military spokesman, said. "It was quite a big bang and we feel very concerned because all of the victims were enjoying a new year's eve music show."

A witness told reporters security was lax. "The security was very weak. Anyone could come and go into the middle of the field and join the crowd in front. The explosion was really loud and, moments after it, people just went wild and tried to run," said construction worker Mohammad Amir.

Most of the victims were young revellers. A baby girl, a seven-year-old boy and three teenagers were among the casualties, a hospital said. Indonesia's police chief had warned on Tuesday that militants might launch attacks on new year's eve. There were no reports of other major violence in the world's largest Muslim nation.

Last May, the Indonesian government launched an offensive against GAM and imposed martial law in the province, on the northern tip of Sumatra island, after negotiations with the rebels in Tokyo failed to find a peaceful resolution.

The military says it has killed or captured about 2,000 GAM members in the offensive - a statement difficult to verify because of travel curbs on the media and others in Aceh.

Several humanitarian groups say civilians are the ones most troubled by the conflict between the government forces and GAM. This week, a clash between the two sides left an Indonesian television journalist dead with bullet wounds.-Reuters