Latest reports say that gunfire has been heard around Turkey's iconic Dolmabahce Palace in Istanbul, a major tourist attraction.

Witnesses claim to have heard the blast, then shooting. Two armed people are being sought over the attack, and one report said they were detained at the scene. No casualties were reported.

Ambulances have been sent to the area and roads have been sealed off.

Separately, media reports said eight Turkish soldiers had been killed by a bomb in south-eastern Siirt province.

The Dolmabahce Palace houses the city offices of Prime Minister Ahmet Davutoglu, but he was in the capital Ankara at the time.

The palace was the main administrative centre of the Ottoman Empire for many years in the 19th and early 20th centuries.

The founder of modern Turkey, Mustapha Kemal Ataturk, died there in 1938.

A man suspected of belonging to the banned leftist group DHKP-C was arrested in January after attacking guards outside the palace.