Two US police officers have been shot dead in ambush-style attacks while sitting in their patrol cars in Iowa.

Officers responded to a report of shots fired at 1.06am and found an Urbandale Police Department officer who had been shot. Authorities from several agencies saturated the area after that shooting, and about 20 minutes later discovered that a Des Moines officer had been shot in a patrol car at an intersection, Des Moines Sergeant Paul Parizek said.

Suspect Scott Greene in a photo released by the Des Moines police department. Photo: via AP

The slain officers were identified as Sergeant Anthony Beminio of the Des Moines Police Department and Officer Justin Martin of the Urbandale Police Department.

The shootings happened about 3km apart and both took place along main streets that cut through residential areas.

Authorities later arrested a 46 year old Iowa man identified as Scott Michael Greene. Parizek said he was taken into custody by the Dallas County Sheriff’s Office, offering no resistance.

There was no explanation as to how a connection was made to Greene as a suspect, but he had been identified beforehand as having information crucial to the case. It’s not clear what his motive was.

Des Moines Sergeant Paul Parizek speaks to media over the ambush–style killings. Photo: AP/Scott McFetridge

However the New York Times says just two days earlier a man police referred to as Scott Greene was escorted from a local high school football game, after he was accused of causing a disturbance.

In a video posted online, the man demands the return of a Confederate flag he had been holding and asks to file charges against the person who confiscated it from him.

The shootings follow a spate of police killings, including ambushes of officers in Dallas and Baton Rouge, Louisiana. Five officers were killed in Dallas on July 7 and three were killed later that month in Baton Rouge.

Parizek said officers are now conducting patrols in pairs for protection.

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