Police have made an apology after a 'pretend suicide bomber' cried 'Allahu Akbar' just before a exercise was staged replicating a terrorist attack at the Trafford Centre.

Greater Manchester Police were criticised on social media following the staged drill last night with people asking why Islam had been chosen as the religion of the fake terrorists.

Garry Shewan, Assistant Chief Constable, responded on Twitter, apologised to anyone who was offended and said the use of the phrase was unacceptable.

'Allahu Akbar' is Arabic for 'God is Greater'.

Watch: Armed police respond to the 'attack'

Video thumbnail, Video shows armed police responding to 'bomb attack' at Trafford Centre during exercise
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He then released a statement repeating the apology and saying it was ‘unacceptable’ to use the phrase.

ACC Shewan said: “For the past 24 hours, GMP, along with other agencies, has been hosting a counter terrorism training exercise based at the Trafford Centre, which began with a mock suicide bomber detonating a bomb inside the shopping centre.

“It is a necessity for agencies including the police to train and prepare using exercises such as this, so that we would be in the best possible position to respond in the event that the unthinkable happened and an attack took place.

Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

“The scenario for this exercise is based on a suicide attack by an extremist Daesh style organisation and the scenario writers have centred the circumstances around previous similar attacks of this nature, mirroring details of past events to make the situation as real life as possible for all of those involved.

“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. We recognise and apologise for the offence that this has caused.”

Manchester GP Siema Iqbal was one of those who prompted the apology.

Watch: Armed police respond to suicide bomber

Video thumbnail, Armed police respond to 'suicide bomb attack' at Trafford Centre during exercise
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She tweeted: “Please provide an explanation @gmpolice @RSutcliffeACC @amandacomms why the terrorist in #CTexercise was #Muslim and shouted Allah Akhbar.”

Dr Erinma Bell MBE retweeted Siema adding: “Good question. We need to move away from stereotypes if we want to achieve Real learning. A terrorist can be anyone.”

The Community Safety Forum said: “This sort of thing panders to stereotypes and further divides us. It will increase anti-Muslim hate crime.”

Injured shoppers. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

Greater Manchester's Mayor and Police and Crime Commissioner Tony Lloyd praised the operation, but also criticised the decision to shout 'Allahu Akbar'.

He said: "This was a very good exercise in preparing for a situation we never want to see, but must be ready for.

"The public expects the highest standard of training where all of our emergency services locally work together effectively with those who with national responsibility to keep the UK safe.

RECAP: Relive the events of last night's exercise

"This planning event has helped ensure that should the unthinkable ever happen, Greater Manchester will be ready.

Mr Lloyd added: "However, it is frustrating the operation has been marred by the ill-judged, unnecessary and unacceptable decision by organisers to have those playing the parts of terrorists to shout ‘Allah Akbar’ before setting off their fake bombs.

Armed response. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

"It didn’t add anything to the event, but has the potential to undermine the great community relations we have in Greater Manchester."

Around 800 volunteers took part in the mock attack which took five months to plan.

It was the latest in a series of exercises which have taken place across the country .

The drill started at midnight at the entrance to The Orient food court when a man dressed all in black walked in and shouted at the crowd.

Dead suicide bomber. Intu Trafford Centre, Trafford, Manchester, United Kingdom. Police in Greater Manchester have joined forces with other agencies to carry out a simulated terror attack to test the emergency response to a major incident. 10 May 2016. Photograph Credit : Sean Hansford

Seconds later an explosion rocked the food hall before a masked gunman appeared and began firing shots.

None of the emergency services taking part in the exercise nor the volunteers were told precise details of the scenario – dubbed Exercise Winchester Accord – but knew it would involve some form of terror attack.

The exercise as a whole was deemed a success.