POLICE are hunting two suspects after at least five people were killed and several more wounded in a multiple shooting at a backyard party in a suburban neighbourhood in Pittsburgh.

Allegheny Police say four men and one woman were killed in the shooting at a house on Franklin Avenue in the suburb of Wilkinsburg, after a gunman barged into the party and opened fire.

Lt Andrew Schurman of the Allegheny County homicide unit said as people were fleeing towards the backdoor of the home, a second gunman fired from the side of the yard — catching them on the back verandah.

Police confirmed four of the five people were dead when police arrived, and four others were transported to hospital.

One person died from their injuries in the hospital.

Two men are critical, and a woman is in a stable condition.

Police are hunting for at least two gunmen who escaped after the shooting. A motive is not known.

One neighbour told CBS Pittsburgh they heard about 25 gunshots ring off.

“I heard at least 20 shots,” a witness, Kayla Alexandra, told WPXI.

Dozens of shell casings littered the pavement of an alleyway near the site, where police were gathering evidence and talking to witnesses.