Philadelphia: At least six police officers were wounded after a gunman opened fire on Philadelphia police on Wednesday afternoon in a standoff that extended into the evening.
A shooter remained active as of 6 pm (local time) in the city's Nicetown neighbourhood, Philadelphia police Sgt. Eric Gripp tweeted.
All the officers' injuries were considered non-life-threatening, he said.
Live video from news stations showed a massive police presence, with dozens of squad cars and officers, many of them with their guns drawn. Gunshots continued to be heard late Wednesday afternoon.