Hospitals across England have been put on standby to deal with another attack amid fears a second explosive device was in the hands of other terrorists.
It comes as officers who raided the home of Manchester suicide bomber Salman Abedi discovered a huge stash of bomb-making materials sufficient to set off more deadly attacks.
Abedi is believed to have honed bomb-making skills in Libya and is feared to have created several devices, which could have been passed to other extremists before launching his attack on Monday (22 May).
"The worry is there was enough to build two or three bombs and we can't rule that out," one security source told the Telegraph.
In response, all hospitals in England, including 27 specialist trauma centre, have been told to "prepare for a further incident" and to prepare for dealing with shrapnel victims.
Chris Moran, NHS England's national clinical director for trauma, sent the message to hospitals on Thursday (25 May).
"The trauma community in Manchester has provided a tremendous response to the atrocity on Monday night and this is a credit to their dedication and clinical skills, and also the preparation that has taken place," Moran wrote, reported the Guardian.
"You will be aware that we have a bank holiday weekend approaching. There are a number of things that all trauma units and major trauma centres can do to prepare for a further incident and I should be grateful if you could disseminate these within your network so that frontline clinicians are aware."
NHS England confirmed that all hospitals should be taking further precautionary measures in the wake of the Manchester attack.
A spokesman said: "Since the [Joint Terrorism Analysis Centre] has announced the threat level has changed from severe to critical, this triggers longstanding, tried and tested NHS protocols reflected in this letter, which reminds NHS organisations of the precautionary measures they need to take ensure care is in place should it be needed."