At least 10 people were killed and many more injured after an explosion rocked a central square in Istanbul this morning.

The blast happened just after 10am local time (8am GMT) in the city's historic Sultanahmet district, a major tourist attraction in Turkey's most populous city.

The blast may have been caused by a suicide bomber, Turkey's Haberturk television said, without citing its sources. Ambulances rushed to the scene and police have sealed off the area, according to Reuters.

While details are as yet unclear, the Istanbul governor's office said 15 people were injured in the blast and 10 have been confirmed dead.

Investigations were being conducted into the type of explosive which caused the blast and those responsible, the governor's office statement said.

Turkey has been hit by sporadic terror attacks by a far-left group in recent months, according to the BBC's Mark Lowen, and violence between government forces and PKK Kurdish militants in south-east Turkey has escalated.

Several recent bomb attacks have also been blamed on Islamic State. More than 100 people were killed by two suicide blasts in Turkey's capital Ankara in October and over 30 were killed in an attacks near the Syrian border in July.

Additional reporting from Reuters.