Arrests after white powder race attacks in Manchester
Four men have been arrested after white powder was thrown at people in racist attacks in north Manchester.
The fire service was called and the substance proved not to be hazardous.
However North Manchester Hospital's A&E department and Collyhurst police station were closed briefly when men arrived there having come into contact with the substance.
The men are being held on suspicion of causing grievous bodily harm with intent and are in police custody.
Det Insp Alex Nicholson said: "We believe there are other victims out there who have had powder thrown onto them. While it is important they seek medical advice it is equally important they call the police.
"The vast majority of victims were black men and we are treating this as a racially-aggravated series of attacks."