Besiktas and the Turkish Football Association have condemned the terrorists who apparently targeted police with a car bomb outside the Istanbul club’s Vodafone Arena.
Turkish President Recep Tayyip Erdogan confirmed there have been fatalities.
The explosion, which reportedly targeted a riot police bus right outside the stadium, took place at round 10.30pm local time following Besiktas’ 2-1 home win over Bursaspor.
The blast was followed by a second one in Macka Park near the stadium which was being treated as a suicide bomb, Turkish Interior Minister Suleyman Soylu said.
“One is located just outside the stadium…and the other is in Macka Park. Macka Park is considered a suicide bomb,” he was quoted by Turkey’s state-run Anadolu Agency.
Turkish media reported the explosions were followed by gunshots.
Erdogan said in a statement that there had been “martyrs and wounded”, but he did not mention a number.
Soylu had said earlier that around 20 people, mainly riot police officers, had been injured.
Images posted on social media appeared to show the remains of a burnt-out vehicle, with debris, and police helmets, strewn across the road and fires burning in the wreckage.
Besiktas, the Turkish Super Lig champions, released a statement condemning “the terrorists…who attacked our heroic security forces, who provided security for both our supporters and those of our visitors Bursaspor”.
The Istanbul-based club added: “We hope that the citizens who were wounded in the attack will have a speedy recovery and that no greater suffering will be experienced.
“We condemn violence and hatred.”
The Turkish FA expressed its “tremendous sorrow” at the injuries and condemned the “inhuman brutal terrorist attack”.
Soylu said the explosion occurred at the exit where Bursaspor fans left the stadium, with the club saying supporters had already left the stadium and that none of their fans had been caught up in the incident.
Bursaspor added that they wished the “injured security personnel and citizens a speedy recovery”.