ISTANBUL — Thirty-eight people were killed and 136 were wounded here on Saturday in two explosions, and officials said one of them was a car bomb outside a stadium that targeted police officers on duty for a soccer game.

Turkey’s interior minister, Suleyman Soylu, speaking from Ankara in comments carried by local media, said the second explosion appeared to be in a nearby park, and may have been a suicide bomb.

The explosions set off activity around central Istanbul, with rushing ambulances, helicopters hovering, and a large plume of smoke rising over the city, scenes that were as familiar as they were frantic. Like last summer’s attempted coup and a devastating attack at Ataturk Airport in Istanbul, the bombs on Saturday came in the late evening, when this megacity’s streets, bars and restaurants were packed.

Shortly after the bombings, Mr. Soylu said that 20 police officers had been wounded. Turkish media later reported that more than a dozen police officers had been killed. Updated casualty numbers were later reported by The Associated Press.