Police secure the area after an explosion in central Istanbul, Turkey January 12, 2016.[Photo/Agencies]

ISTANBUL - An explosion rocked a square in the heart of Istanbul's historic Sultanahmet tourist district on Tuesday, killing 10 people and injuring 15, according to a statement on the website of Istanbul governor's office.

Ambulances rushed to the site in Sultanahmet square, close to the Blue Mosque and Hagia Sophia, in a major tourist area of Turkey's most populous city, ferrying away the wounded as police cordoned off streets.

"We're taking precautions against a second explosion," the police officer said, ushering people out of the square.

Turkey's AHaber television said the blast may have been caused by a suicide bomber but this was not independently confirmed.

"The explosion was very loud. We shook a lot. We ran out and saw body parts," one woman who works at a nearby antiques store told a Reuters correspondent, declining to give her name.

Kurdish, leftist and Islamist militants have all carried out attacks in Turkey in the past.

Turkey has also become a target for Islamic State, with two bombings last year blamed on the radical Sunni Muslim group, in the town of Suruc near the Syrian border and in the capital Ankara, the latter killing more than 100 people.