At least one person was dead and six others wounded after a suicide bomber blew himself up at a police station in Indonesia on Wednesday, that also killed him, according to authorities.

The explosion happened around at the compound in Medan on Sumatra island during morning roll call.

The motive for the attack was not unclear but police stations have been frequent targets for radicals in the world’s biggest Muslim majority nation, which has long struggled with Islamist militancy.

“For now, we believe he was a lone wolf,” national police spokesman Dedi Prasetyo told reporters in Jakarta.

“The anti-terror squad and forensics unit are still examining the crime scene,” he added.

At least six people were wounded in the blast, including four officers and two civilians, but their injuries were not severe, he added.

Police said the attacker was active on social media, while CCTV footage showed him entering the compound wearing a uniform worn by drivers of a popular ride-hailing service.

The attack came a day after Indonesia launched a website that lets the public report “radical” content posted by government workers, including material that promotes hate or intolerance.

In August, authorities shot and arrested a militant who attacked officers at a station in Indonesia’s second-biggest city, Surabaya,

In June, in another incident, the suicide bomber was seriously wounded after he tried to blow himself up outside a police building on Java island.

Last month, Indonesian President Joko Widodo ordered beefed-up security after two militants from an Islamic State-linked terror group stabbed his chief security minister.

(With inputs from AFP)