International

Several people are believed to have been killed in an explosion in a tourist district of the Turkish city of Istanbul.

Ambulances were said to have rushed to the Sultanahmet Square, next to the city's famous Blue Mosque landmark, where the blast was reported.

Several more have been injured, according to Turkish media.

Police have sealed off the scene, which is said to be in a park near an obelisk.

Witnesses and a police officers told Reuters they saw the remains of at least one person.

State run TRT TV station said a suicide bomber is thought to have been responsible.