The Arabic phrase means ‘God is Great’, and it was used as part of the training initiative designed to test the response of emergency teams.
The scenario for the exercise was based on a suicide attack by an extremist ISIS-style organisation, according to assistant chief constable Garry Shewan from Greater Manchester Police.
“However, on reflection we acknowledge that it was unacceptable to use this religious phrase immediately before the mock suicide bombing, which so vocally linked this exercise with Islam,” he said.
“We recognise and apologise for the offence that this has caused.”
The training began at midnight in the Trafford Centre when a man pretending to be a suicide bomber entered the crowded centre before acting as if he detonated a bomb.
There was also hundreds of volunteers who played the role of shoppers and the sound of gunfire was heard in the shops.
The volunteers screamed and ran away, while others were covered in fake blood and lying on the ground.
Greater Manchester's mayor and police and crime commissioner Tony Lloyd added that it was an “ill-judged, unnecessary and unacceptable decision by organisers to have those playing the parts of terrorists to shout 'Allahu Akbar' before setting off their fake bombs”.
“It didn't add anything to the event, but has the potential to undermine the great community relations we have in Greater Manchester,” he said.
Meanwhile, one million people who work in crowded places in the UK are to be trained over the next 12 months in dealing with a possible terrorist attack.
The aim is to ensure that employees are aware of the risk of terrorism and how to react in the case of such a real scenario.
The plan will see staff pass on police terror training and advice to colleagues.
In particular, companies based in busy city centres and those in the entertainment, sports and retail sectors will be prioritised for the training.
Police in the UK have apologised for the shouting of the phrase “Allahu Akbar” at the beginning of an anti-terror training program.