Lhokseumawe – Five grenade blasts Tuesday rocked the headquarters of the air defence battalion in Indonesia's troubled Aceh province but there were no casualties, the military said.

The early morning attack on the base in this major city in Sumatra island came a week after soldiers, including some from the base, opened fire at civilians leaving at least 41 civilians dead.

"The attack happened at 12.30am but no one was injured," a resident source told AFP.

The Indonesian military accused rebels from the Hasan Tiro separatist group of launching grenades and firing shots at the headquarters, the Antara state news agency said.

"Using a grenade launcher, the Hasan Tiro group fired at five targets," Antara quoted a military statement as saying. The military classified the damage as minor and said the attackers fled after the attack. One person was arrested on Monday for behaving suspiciously around the base, Antara said.

A team from the National Commission on Human Rights and military leaders made a visit to the base in Pulau Rungkom village later on Tuesday.

It had been the destination of a mass protest by thousands of villagers on May 3 but the crowd met with soldiers before reaching it. The shooting started shortly afterwards.

The people were trying to protest violence by soldiers from the base at a nearby village on the previous day.

"I could hear the loud blasts last night, and the origin of the sound came from where the artilerry base is, but am not sure myself," a resident whose home lies some three kilometers away from the base told AFP by phone.

"I was shocked but did not dare go out," he said, adding that life resumed as normal in downtown Lhokseumawe Tuesday.

Many staunchly-Moslem Acehnese deeply resent the military after 10 years of harsh operations in the province designed to try to wipe out the separatist Aceh Merdeka (Free Aceh) movement.

Aceh Merdeka has been fighting for an Islamic state in the province, at the northern tip of Sumatra island, since the mid 1970s. There have been rising calls for a self-determination referendum in recent months.