Turkish President Recep Tayyip Erdogan has defended his country's fight against Kurdish fighters in Syria as "legitimate defense", after international powers urged Ankara to rein in its cross-border bombardments, AFP reports.

Turkey has been shelling targets in northern Syria for the past week in a bid to stem the advances of a Kurdish-led coalition that has seized territory in the area.

Ankara blames Syrian Kurdish fighters for this week's suicide car bomb attack in the Turkish capital that killed 28 people and fears the creation of a Kurdish stronghold along its southern border.