A suspected female terrorist carried out an attack targeting the offices of a non-governmental organization (NGO) in Istanbul’s Gaziosmanpaşa district early Thursday.

According to security footage, the explosion took place shortly after a woman came near the building and left it at around 5:40 a.m. local time (2:40 a.m. GMT).

The building, located in the Hürriyet neighborhood, housed the office of the Turkey Youth Foundation (TÜGVA), Anadolu Agency (AA) reported.

No casualties were reported after the explosion.

Initial investigations suggested that the explosion was caused by a stun grenade.

While no terrorist group has claimed responsibility for the attack, the PKK terrorist group carried out an attack targeting a vehicle carrying prison guards in Bursa province a day earlier.

Police have cordoned off the area and are still investigating the incident.