A suicide bomber wounded at least 26 people when he struck a prayer room in an Indonesian police compound in the first suicide attack on a mosque in the country, police said.

The bomber began the Friday prayers along with other worshippers, and was killed immediately in the explosion at around 12.15 p.m. (0515 GMT) at police headquarters in the city of Cirebon, West Java province, they said.

The blast appeared to mark a return of major terror attacks to Indonesia after almost two years, and followed a series of arrests of suspected Islamist extremists.

“The blast occurred at the beginning of Friday prayers,” said police spokesman Anton Bachrul Alam.

“The man was praying in the third row. Suddenly there was a blast,” an eyewitness named Anton was quoted as saying by Detik news website.

The explosion injured several local police officers, including the Cirebon police chief, who were praying around the attacker.

Police said they were still trying to identify the bomber – who was wearing dark clothing and was thought to be in his late 20s – and his motives.

It was the first time a suicide bomber had targeted people inside a mosque in Indonesia, the world’s most populous Muslim-majority country, Narapatih Centre terror analyst Mardigu Prasantyo said.