Anti-terrorist squads stand guard outside the bombing site at Santa Maria church in Surabaya, capital of Indonesia's East Java Province, May 13, 2018. Six people were killed and at least 35 others injured as suicide bombers blew themselves up during congregations in three churches in Surabaya on Sunday, provincial police spokesman Frans Barung said. The blasts took place in Santa Maria church, Gereja Kristen Indonesia church and Pentecostal church. (Xinhua/Kurniawan)

JAKARTA, May 13 (Xinhua) -- Six people including policemen and bombers were killed and at least 35 others injured as suicide bombers blew themselves during congregations in three churches in Surabaya city, capital of Indonesia's East Java province, on Sunday, a police officer said.

The explosions killed two persons in Pantekosta church in Arjuno street, one in Gereja Kristen Indonesia on Dipengoro street and three in Santa Maria church on Ngagel Madya street, provincial police spokesman Frans Barung said.

"There are three locations (churches) of the explosions," he told the media.

The victims have been rushed to hospital in the city for medical treatments, said the spokesman.

The first deadly blast took place in Santa Maria church at 07:15 a.m. Jakarta time and was followed by others with the interval time of about five minutes, he said.

The attackers, disguising as followers of the morning sermons in the three churches.

The police have cordoned off all the scenes for investigation, said the spokesman.