Details about the mass shooting overnight scarce, but emergency services are responding
Two gunmen have ambushed a backyard party near the northern US city of Pittsburgh - killing at least five people and wounding several others.
Local TV station WTAE Pittsburgh reports those responsible fled the scene, and are still at large.
The attack is the latest in a series of mass shootings that have elevated gun control as an issue in the US Presidential election.
The attack happened around eight miles east of the city.