A Kurdish militant group claimed responsibility for the terrorist attack – the latest in a series of deadly blasts across politically turbulent Turkey this year.
Turkish interior minister Suleyman Soylu said 13 people had been arrested in connection with the atrocities.
A car bomb was the first to go off, followed moments later by a suicide bomber.
The attack was aimed at police officers in retaliation to what the militant group perceived as state-sponsored violence in the Turkish southeast, AP reports.
Thirty of the fatalities were police, seven were civilians, and one remains unidentified.
“What we must focus on is this terror burden. Our people should have no doubt we will continue our battle against terror until the end,” Turkish president Tayyip Erdogan said, as reported by David Dolan and Tuvan Gumrukcu from Reuters.
The death toll continued to increase in the hours after the bombs were detonated.
The first occurred around 10:30 p.m. local time, following a match between Super Lig champion Besiktas and visitor Bursaspor.
“We strongly condemn this horrible act and send our support to the Turkish Football Federation, Besiktas, and Bursaspor football clubs,” UEFA said in a statement.
Besiktas confirmed it lost two employees in the attack. Bursaspor announced Saturday evening none of the injured were travelling supporters of the away side.
Most fans would’ve left the stadium by the time of the attacks, though Erdogan said the militants attempted to maximize the number of fatalities.
Dozens of ambulances swarmed the scene in response to the vehicle that exploded beside the arena. The other culprit committed suicide in nearby Macka Park.
At least half a dozen mass assaults have jarred the country in 2016, all of them committed by Kurdish militants and followers of the Islamic State, the BBC’s Mark Lowen reports.
A media blackout was ordered before Turkey announced a national day of mourning.