Updated / Dec. 11, 2016 08:41

Turkey has declared a day of national mourning, after two bombs killed 30 people and wounded 155 others in a coordinated attack on police outside a soccer stadium in Istanbul after a match between two top teams.

A car bomb exploded outside the Vodafone Arena, home to Istanbul’s Besiktas soccer team, leaving flaming wreckage on the street.

Forty-five seconds later, a suspect wearing explosives detonated them while surrounded by police in an adjacent park, Deputy Prime Minister Numan Kurtulmus told a news conference.

President Tayyip Erdogan described the blasts as a terrorist attack on police and civilians.

He said the aim of the bombings, two hours after the end of a match attended by thousands of people, had been to cause the maximum number of casualties.

The deputy PM said there are indications that the attacks were carried out by Kurdish militants.

But the blasts came less than a week after the so-called Islamic State urged its supporters to target Turkey’s “security, military, economic and media establishment”.

Turkey is a member of the NATO military alliance and part of the US-led coalition against Islamic State.

It launched a military incursion into Syria in August against the radical Islamist group. It is also fighting a Kurdish militant insurgency in its own southeast.

Interior Minister Suleyman Soylu said the first explosion, which came around two hours after the end of the match between Besiktas and Bursaspor, was at an assembly point for riot police officers.

The second came as police surrounded the suicide bomber in the nearby Macka park.

Seven of those killed in the blasts were civilians, 30 were police officers, including a police chief and another senior officer, with one unidentified person.

Mr Soylu also said 13 people had been detained based on evidence from the detonated vehicle, but gave no indication of who the authorities thought might be behind the attack.

A Reuters photographer said many riot police officers were seriously wounded.

A police water cannon doused the wreckage of a burned-out car and there were two separate fires on the road outside the stadium.

Bursaspor said none of its fans appeared to have been injured. Both it and Besiktas condemned the bombings.

NATO Secretary General Jens Stoltenberg condemned what he described as “horrific acts of terror”, while European leaders also sent messages of solidarity.

The United States condemned the attack and said it stood with its NATO ally.

The bombings come five months after Turkey was shaken by a failed military coup, in which more than 240 people were killed, many of them in Istanbul.

Istanbul has seen several other attacks this year, including in June, when around 45 people were killed and hundreds wounded as three suspected Islamic State militants carried out a gun and bomb attack on its main Ataturk airport.