The governor of Istanbul, Muammer Guler, confirmed the deaths following the attack Wednesday on a police checkpoint.

Television stations CNN-Turk and NTV said police returned fire after gunmen jumped from a car and began shooting. Officials have labeled the attack a "terrorist" act.

One police officer is said to have died at the scene, while the other two died in a nearby hospital. Two other people - a policeman and the driver of a truck - were wounded in the exchange.

A U.S. Embassy spokeswoman said there were no reports of injuries among consulate personnel.

Police are searching for a fourth assailant who drove away from the scene.

Some information for this report was provided by AFP, AP and Reuters. - VOA News