Two bomb blasts near an Istanbul stadium after a soccer match ended killed 38 people and wounded 155 others in an attack that appeared to target police, Turkey's interior minister and officials said.
Thirty of the dead are police officers, Turkish Interior Minister Suleyman Soylu said in an address early Sunday.
Deputy Prime minister Numan Kurtulmus declared a day of mourning, as he confirmed thirteen people have so-far been detained in connection with the attack
The first bomb exploded at around 10:30 p.m. as law enforcement left the newly built Vodafone Arena Stadium, where home side Besiktas were playing Bursaspor, Turkish security forces said.
Soylu called the bombings a "cruel plot," NBC's British partner ITV News reported. The first blast, which took place on a hill overlooking the stadium, is believed to have been a car bomb, Soylu told reporters.
The car bomb was detonated by remote control, Soylu said. The second explosion struck Macka Park and was believed to be a suicide bomb.
"We have once again witnessed tonight in Istanbul the ugly face of terror which tramples on every value and decency," Turkish President Recep Tayyip Erdogan said in a statement.
Of the 155 injured, 14 were in intensive care and five of those victims were in critical condition, Turkey's state-run Anadolu Agency reported.
There was no immediate claim of responsibility for the attack. This year Istanbul has witnessed bombings attributed by authorities to the ISIS terror group or claimed by Kurdish militants.
The private NTV channel said the target of the attack was a bus for riot police.
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. One witness reported hearing over 100 shots after the explosions.
A witness who saw one of the blasts, Nihat Yildiz, told the Anadolu Agency the explosions occurred within one minute of each other.
"We saw a huge flame along with the blast. The windows of the restaurant broke into pieces with the pressure of the explosion. Then we heard gunfire for two minutes," he told the news agency.
A taxi driver at the site of the Istanbul bombings said their force made him hit his head on the taxi meter and that his ears were still ringing from the blasts and screaming that followed.
"Amid the screams I heard an officer saying 'do not shout! Do not make them (the perpetrators) be satisfied," said Ismail Coskun.
Turkey's radio and television board issued a temporary blackout on coverage of the explosion that occurred Saturday in Istanbul citing public order and national security reasons. The order asks media organizations to refrain from broadcasting and publishing anything that may cause "fear in the public, panic and disorder and which may serve the aims of terrorist organizations."
The American embassy in Turkey stated its condolences and support for the country via Twitter. NATO Secretary General Jens Stoltenberg condemned the "horrific acts of terror" in the city.
The Bursaspor team communicated via Twitter that none of its fans had been injured. The team "strongly condemned" terrorism and the attack in a statement posted on its website and said "we wish a speedy recovery to our wounded citizens."
Before the explosion Besiktas won the match 2-1.
The Union of European Football Associations expressed its "deepest condolences" to victims of the bombings, and said it sends its support to the Turkish Football Federation and the Besiktas and Bursaspor clubs.