Indonesian war planes early today fired rockets at a rebel base in the restive province of Aceh, signaling the start of a military offensive just hours after the breakdown of peace talks.

Three planes fired the rockets at a stronghold of the Free Aceh Movement 12 miles east of the capital of Banda Aceh, said Maj. Gen. Erwin Sujono.

“The offensive has begun,” Sujono said in Banda Aceh. It was unclear if there were any casualties.

Sujono added that 15 warships had moved into waters close to the northern town of Lhokseumawe, an area that is heavily populated with rebels.

Earlier today, six C-130 Hercules transport aircraft released 458 soldiers over an airstrip close to Banda Aceh in a show of force after Indonesia announced a crackdown and martial law in the province.

A state of emergency was announced at midnight on Sunday after talks in Tokyo aimed at salvaging a Dec. 9 cease-fire accord broke down. Martial law gives the military sweeping powers to make arrests, impose curfews and stop people from entering or leaving the province.

Armed with the new powers, the military immediately arrested five senior rebels who had played a key role in negotiating the December peace deal in Geneva.

Today’s attack using U.S.-made OV-10 Bronco war planes was the first time in several years that the military has used air-to-surface missiles in Aceh. The military said the target was an alleged weapons cache in the rebel camp.

President Megawati Sukarnoputri signed a decree authorizing war in the oil- and gas-rich province after a rebel delegation in Tokyo rejected Jakarta’s demand to lay down their weapons and accept autonomy instead of independence.

The Dec. 9 agreement halted the 26-year insurgency in the province 1,200 miles northwest of Jakarta, but the accord unraveled in recent months after violence by both sides.

The Tokyo talks were arranged under pressure from international donors alarmed by the prospect of a return to hostilities in Aceh, where more than 12,000 people have died in fighting since 1976.