The explosion that occurred on April 11 at a police building in the southeastern province of Diyarbakır was a terror attack, Interior Minister Süleyman Soylu has said.

In an interview with private broadcaster Habertürk, Soylu said the attack was staged through a tunnel dug from outside and was placed with explosives.

According to hurriyetdailynews previously, the Diyarbakır Governor’s Office stated that the explosion had occurred during the repair of a police panzer in the additional building of police headquarters in the central Bağlar district.

One police officer and two civilian personnel were killed in the explosion. Around 12 people were also wounded, according to the minister.

Separately, five suspects were detained on April 12 as a part of the investigation into the attack, Doğan News Agency reported.

The police building was the scene of an outlawed Kurdistan Workers’ Party (PKK) car bomb attack on Nov. 4, 2016, that killed nine people and injured over 100.