Updated: Bomb kills 10 in tourist city popular with Irish holidaymakers

An explosion in the heart of Istanbul's historic Sultanahmet tourist district has killed at least ten people and wounded 15.

Some local media reports said a suicide bomber may have been responsible.

Several bodies were witnessed lying on the ground in the Sultanahmet square, close to the famous Blue Mosque and Hagia Sophia landmarks, a major tourist area of Turkey's most populous city.

The Istanbul governor's office said the authorities were investigating the type of explosive used and who might have been responsible for the attack.

It said ten people were killed and15 wounded but gave no further details.