Two explosions at a sports stadium in Istanbul have left 13 dead and dozens injured.

At least one of the blasts was caused by a car bomb and targeted a riot police bus near the Besiktas stadium, interior minister Suleyman Soylu said.

The interior ministry said that a number of police officers had been wounded but said it had no information of whether anyone had been killed.

TV footage showed fires burning outside the stadium, which is also called the Vodafone Arena.

Pictures from the scene also showed the shattered wreckage of a vehicle.

Police sealed the area, setting up a wide cordon around the stadium where a match between Besiktas and

Bursaspor football clubs had ended more than an hour before.

Witnesses said a second explosion and gunfire were heard, but the reports remain unconfirmed.

One Turkish broadcaster said the blast targeted a police vehicle that was leaving the stadium after fans had already dispersed.

Bursapor said it had received no reports of injured fans.

Mr Soylu told Turkey's state-run Anadolu Agency: "It is thought to be a car bomb at a point where our special forces police were located, right after the match at the exit where Bursaspor fans exited, after the fans had left.

"We have no information on the number of dead. God willing we hope there won't be any. The wounded are police.