The Police chief informed the press here on Monday that the attackers had used two motorcycles with explosive bombs.
"They were five suicide bombers, who belonged to one family," Karnavian stated.
During the attacks, they blew themselves up. Four of them died.
"They were attempting to enter the complex, but the security was tight. When they were stopped, a police car was entering, and the explosion then occurred. Four of them died and one of them, a child, was seen stumbling around after the blast and survived," he revealed.
He remarked that the explosion had injured a police officer, who survived the bomb blast. The attackers belonged to the same group of suicide bombers that had attacked three churches in Surabaya and killed 13 and injured 43 others in Surabaya on Sunday.
They belong to the cell of the Jamaah Ansharud Dualah, an extremist group affiliated with the Islamic State (IS or ISIS) network.
"Why did they launch attacks in Surabaya? This is because they have control over this region. Why did they carry out the attack? It is because they received instructions from the ISIS in Syria," the Police chief noted.
Karnavian stated that the suicide bombing in Surabaya was not a new phenomenon, and it was not the first time either that such an attack involved women. However, this is the first time that they were successful in exploding the bomb with women.
During the New Year, the police had succeeded in aborting an attempt by a pregnant woman to conduct a suicide bombing. She was then taken to the Police`s Mobile Brigade Headquarters. Several months later, the woman delivered a baby.
"The suicide attack by a woman is not the first time it has occurred in the world," he noted, adding that it had also taken place in India, Syria, and Iraq.
"The ISIS has practiced this in Syria using children. It is saddening and is not linked to any religion but related to the network at home, the region, the Philippines, and the Middle East. We will work harder to handle it," the National Police chief stated.
Earlier, East Java Police Spokesman Senior Commissioner Frans Barung Mangera remarked that an explosion had occurred at the Surabaya police headquarters at 8:50 a.m. local time on Monday.
"There was an explosion at the Surabaya police headquarters at 8:50 a.m. local time," Mangera stated.
While delivering a statement to the press, Mangera could not as yet provide information on whether the explosion had claimed lives but confirmed there were some victims in the incident.
"We confirm there are victims in the incident but whether they were killed or injured, please wait for further information," he noted, adding that the victims were police officers and civilians.
Reported by Indra Setiawan/Willy Irawan