An explosion on a highway overpass near a subway station in Istanbul wounded five people and was caused by a bomb, a local mayor has said.

The bomb was left on barriers on the overpass, said Atilla Aydiner, the mayor for Istanbul's Bayrampasa district. Earlier, Istanbul's governor said one person was slightly injured in the blast.

The explosion occurred at 3.30pm GMT at an overpass near the city's Bayrampasa subway station, on the European side of Istanbul. Several ambulances and police vehicles were sent to the area.

The Dogan news agency said it was a hand-made cluster bomb. Dogan also obtained closed-circuit TV footage showing a white van on the overpass, with large holes in its windshield, apparently damaged in the explosion.

The Anadolu Agency identified an injured person as a 36-year-old man and said he was not in a serious condition. It was not immediately clear if he was in the vehicle at the time of the explosion.

Subway services at Bayrampasa and elsewhere were briefly disrupted following the explosion.

Kurdish rebels fighting Turkey for autonomy in the mainly Kurdish south-east of the country have carried out bombings in Istanbul in the past.

Fighting between rebels belonging to the Kurdistan Workers' Party, or PKK, and government forces flared up again in July, killing hundreds of people and derailing a fragile peace process with the Kurds.

Two suicide bombings, blamed on a local cell of the Islamic State group, killed 130 people in a town near the border with Syria in July, and in the capital, Ankara, in October. A banned left-wing group is also active in Istanbul.