A suspected car bomb outside a major soccer stadium in Istanbul has left more than a dozen people dead according to security sources in the Turkey.

Witnesses said more police were deployed and had cordoned off the area as smoke rose from the newly built Beșiktaș stadium. They said gunfire had also been heard in what appeared to have been an armed attack on police.

Broadcaster NTV said 38 people had been wounded but gave no details of any death toll and said the explosion seemed to have targeted a police vehicle that was leaving the stadium after fans had dispersed.

Another explosion was thought to have been caused by a suicide bomber, Turkish interior minister Suleyman Soylu told reporters in comments broadcast live on television.

The suspected suicide bomber struck in Macka park, next to the Vodafone Arena, home to Istanbul’s Besiktas soccer team, while the second explosion hit directly outside the stadium, Soylu said, describing the attack as a “cruel plot”.

Speaking earlier, Soylu, said the wounded were police officers. “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,” he said.

Crime scene investigators at the scene of the explosion. Photograph: Sedat Suna/EPA
Prime minister Binali Yıldırım and Istanbul governor Vasip Şahin had been notified, Turkey’s state-run Anadolu news agency said.

Two witnesses told Reuters they had heard two blasts outside the Vodafone Arena, which lies on the edge of the Bosphorus in central Istanbul and is home to the Beşiktaş soccer team. A Reuters photographer said many riot police officers were seriously wounded.

“It was like hell. The flames went all the way up to the sky. I was drinking tea at the cafe next to the mosque,” said Omer Yilmiz, who works as a cleaner at the nearby Dolmabahçe mosque. “People ducked under the tables, women began crying. Football fans drinking tea at the cafe sought shelter. It was horrible.”

Armed police sealed off streets around the stadium. A police water cannon doused the wreckage of a burnt-out car and there were two separate fires on the road outside the building. Images broadcast on television showed more than a dozen ambulances on a street hugging the stadium and a police helicopter flying overhead with its search lights on.

Turkish soccer team Bursaspor said none of its fans appeared to have been injured in the explosion. “We have contacted our fan groups. There appear to be no injuries among our fans. We wish injured citizens a quick recovery,” Bursaspor said in a statement on its Twitter account.

In a tweet, Turkey’s transport minister, Ahmet Arslan, referred to the bombing as a terrorist attack.