Washington, Aug 5 (DPA) A gunman opened fire in a fitness centre outside Pittsburgh, Pennsylvania, killing at least four people and wounding 10.

Police in Allegheny County, Pennsylvania, said the gunman was believed to be among the dead in Tuesday evening's shooting, in addition to at least four victims, the Pittsburgh Post-Gazette reported on its website.

Public relations officials from the hospitals that received shooting victims said most or all were younger women, several with multiple bullet wounds.

Witnesses told the newspaper that the gunman walked into the fitness club with a duffel bag before drawing a rifle, which he turned on a women's exercise class.