At least seven others were wounded.

The attack took place in Turkey's largest city at around 11 o'clock in the morning, local time.

The bomber first threw a grenade into the building, before blowing himself up near the entrance.

"We heard a noise as we were having breakfast. Because there's a marble factory next to the police station, we thought that the noise was coming from there. Suddenly, we saw ambulances and we realised it was something serious. We came here to see what happened," said one man living nearby.

So far, no one has claimed responsibility for the bombing. However, it could be linked to Kurdish separatist movement - the PKK - internationally listed as a terrorist organisation.

Another cause could be Turkey's support for the rebels in Syria who are trying to overthrow the regime.