Police report an active gunman is on the loose after opening fire during a Sabbath prayer service inside the Tree of Life Congregation Synagogue in the Squirrel Hill neighborhood of Pittsburgh. He is initially reported to have shot eight people and four are dead, including two police officers. Police have placed a cordon around the synagogue and are beginning to evacuate worshippers trapped inside the building. Ambulances and heavy police forces are on the scene. They are sheltering against gunfire coming from inside the synagogue.