A double decker bus with 25 passengers on board has had its roof ripped off, injuring many.
Twenty-five people were believed to be on board.
Greater Manchester Police (GMP) said that a man and woman have sustained "serious" facial injuries and others have been injured.
GMP said they were called to the scene on Milkstone Road, Rochdale, at 12.27pm.
Fire and ambulance crews were also called to the scene.
GMP Traffic tweeted that 17 people had been injured, including one with a broken jaw.
It said: "UPDATE re Rochdale RTC. 17 injured, 1 seriously with a broken jaw. Bridge checked, Trains running normally."
Jackie Brennan, who was at the scene, tweeted ": #Rochdale bus crash round corner from where I work #holycrap".