A suicide bomber detonated a car bomb outside a police headquarters near Turkey's border with Syria, killing four people, including a pregnant police officer, Turkish officials said.
As many as 30 people were injured due to the explosion Wednesday in the town of Midyat in the Kurdish majority southeast Mardin province.
Reinforcements from the security forces were being sent to the area.
Clashes with militants
Clashes reportedly broke out between Turkish forces and Kurdistan Workers Party militants as the attack took place.
Turkish Interior Ministry officials say authorities have strong evidence the PKK carried out Tuesday's attack in Istanbul and the Wednesday bombing in Mardin.
There has been no claim of responsibility for Tuesday’s explosion that left 11 people dead.
PKK has been targeting Turkish police and military since July in its struggle for autonomy in Turkey's southeast.
An estimated 500 Turkish security personnel have been killed while fighting with the Kurdish rebels, according to the military, which claims to have killed up to 4,900 PKK militants in Turkey and northern Iraq.
PKK has been targeting Turkish police and military in its struggle for autonomy in Turkey's southeast.
Prime minister Yildirim spoke after visiting those injured in an attack in Istanbul that occurred just a day before, killing 11 people, including seven officers, and wounding 36 others during the morning rush hour.