People with blood group O negative are being urged to donate in the wake of the Manchester terror attack.
Health chiefs have said hospitals in Manchester have the required amount of blood to deal with the aftermath but group O negative is low.
Bosses are urging people to make an appointment in advance.
Police say 22 people were killed and dozens more were injured when a suicide bomber detonated a device close to the exit of Manchester Arena where 21,000 were watching US pop superstar Ariana Grande.
Mike Stredder, Director of Blood Donation at NHS Blood and Transplant said: "We are responding to last night’s events in Manchester. Our thoughts are with the people affected by this tragic incident.
"Thank you for thinking of giving blood at this time. We do have all the blood required for hospital patients at the present time.
"If you have an appointment to give blood in the next few days, please do your best to keep it, particularly if you are blood group O negative."