Indonesian police during the Bandung standoff.

Indonesian police said they shot and killed a suspected militant in the West Java capital of Bandung on Monday after his bomb exploded in a vacant lot and he fled into a municipal building and set it alight.

National police chief Tito Karnavian said the man was a member of Jemaah Ansharut Daulah, which was designated a terrorist organization by the US in January. Members of the militant group have contacts with Bahrun Naim, an Indonesian fighting with the ISIS group in Syria who has instigated several attacks by JAD in Indonesia.

Karnavian said the attacker wanted fellow Islamic militants who are in prison to be released.

“What we know is that he is from JAD, but we are still not sure whether he has contact with Bahrun Naim,” Karnavian said. “Clearly he wanted his friends to be released.”

West Java police spokesman Yusri Yunus said the attacker was shot in the stomach and died on the way to a hospital.

No one apart from the suspected militant was injured in the attack, which triggered a massive police response and gunbattle. TV footage showed police storming the municipal building as black smoke billowed from its upper floors.

Indonesia has carried out a sustained crackdown on Islamic militants since the 2002 bombings on the tourist island of Bali killed 202 people, mostly foreigners. The arrests of hundreds of militants and the killings of leading figures have neutralized the Jemaah Islamiyah militant network, which was responsible for the Bali bombings and other attacks, but a new threat has emerged from ISIS-inspired radicals.

An attack in January 2016 in Jakarta, Indonesia’s capital, killed eight people, including four attackers. Other recent attacks have killed only the perpetrators or been foiled by counterterrorism police, including a December plot to bomb a guard-changing ceremony at the presidential palace, a popular attraction in Jakarta.

Yunus said another person may have been involved in Monday’s attack because witnesses told police they saw two men on a motorbike arrive at the lot where the bomb exploded and one of them riding away following the explosion.

The low-explosive bomb exploded about 50 meters (55 yards) from the municipal building. Yunus said the man who entered the building was armed with a gun and apparently had explosives in a backpack. When police called on him to surrender, he responded by throwing out an explosive.

All workers in the building escaped after the attacker ran into it. TV footage showed police using a ladder to help some people out through the building’s windows.

Iwan, a Bandung resident identified by one name, told MetroTV that he heard the explosion and saw residents and students chasing the attacker as he ran to the building, yelling, “Terrorist! Terrorist! Catch him!”