Istanbul explosion: 'At least 10 dead' in city's central Sultanahmet Square

At least 10 people are reported to have been killed in an explosion in a central square in Turkey's biggest city, Istanbul.

Istanbul's governor's office says at least 10 people have been killed and 15 injured in Sultanahmet Square, close to the major tourist attractions of the Blue Mosque and Hagia Sophia.

Witnesses and a police officer reported seeing body parts after the blast.

Turkish police have sealed off the square and stopped people from approaching in case of a second explosion.

Authorities are investigating the cause of the blast, but state-run TRT television says it was likely caused by a suicide bomber.

Additional reporting by agencies