Blood donors are being encouraged to keep their appointments to give blood following the explosion at a concert in Manchester.
NHS Blood and Transplant (NHSBT) said it has enough blood stocks at present so no additional drives are planned.
But it encouraged donors who have already planned to donate in coming days to keep their appointments - particularly if they are blood group O negative.
O negative blood is rare but it is the only blood type that can be given to anyone, regardless of their blood type.
Mike Stredder, director of blood donation at NHSBT, 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."
Meanwhile, overnight health workers visiting Manchester offered support to local hospitals treating the wounded.
Kirsty Withers, a theatre clinical manager at University Hospitals of Morecambe Bay (UHMB) NHS Foundation Trust, offered assistance to Manchester Royal Infirmary online, writing: "We are visiting for a health conference from morecambe bay trust tomorrow 3 Theatre ODPs available if needed."
Stuart Hosking-Durn, an emergency preparedness, resilience and response professional with UHMB, also used Twitter to offer help, posting: "do you need extra hands, we have staff in Manchester, have ID and can attend."
Mancunian GP Faizan Awan tweeted: "If you need any help doing clinical work either on wards or minors, let me know. Can be with you in 10 minutes."
North West Ambulance NHS Trust sent 60 ambulances to the scene at Manchester Arena.
It said that 59 casualties had been taken to nearby hospitals and a number of walking wounded were treated at the scene.
Greater Manchester Police said the injured were being treated at six local hospitals.
Urgent appeal for blood at Manchester Royal Infirmary. Please Share! pic.twitter.com/gcWDUBqaYp— Alex Barns (@AlexBarns4) May 23, 2017
Niall Dickson, chief executive of the NHS Confederation, which represents health service organisations in England, Wales and Northern Ireland, said: "Our thoughts are with everyone affected by this shocking tragedy.
"Together with the other emergency services, frontline NHS responders, managers and other staff have once again responded superbly to a major incident and are providing the treatment, care and support that is needed.
"It is at times like these that as a society we really appreciate how important the health service is in all our lives."
The Royal College of Emergency Medicine praised staff in the city for their efforts.
A spokesman said: "Emergency medicine and emergency care staff in the Greater Manchester area are working tirelessly to help and support those injured in the attack.
"The college thanks all staff for their hard work, compassion and dedication during this difficult time."
:: To find out more about blood donation visit www.blood.co.uk or call 0300 123 23 23.
Global health leaders have condemned the terror attack.
Officials at the World Health Organisation's (WHO) 70th World Health Assembly in Geneva, Switzerland, held a minute's silence to remember those killed or injured by the explosion.
Dr David Nabarro, British candidate for the position of WHO director-general, told delegates: "I would like to express my condolences to the people of Manchester after the tragic events of last night.
"I also want to share my feelings of solidarity with the health care workers and responders who every day selflessly put themselves in harm's way to help others.
"When tragic events occur, we see time and time again all over the world, incredible responses of kindness and humanity from people and communities caring for each other and refusing to give in to those who would do us harm."
Ethiopian candidate for the position Dr Tedros Adhanom Ghebreyesus told delegates: "We woke up to the news this morning to the news of a senseless and ruthless terrorist attack in Manchester.
"I condemn it in the strongest term possible.
"My thoughts and prayers are with the victims, their families and the people of the United Kingdom."