MediaBodyguard | Close Protection | Celebrity Security's video: Simulated Allahu Akbar terror attack Manchester shopping centre

Manchester's Police Commissioner says shouts of 'Allahu Akbar' during an anti-terror operation may undermine community relations. Police have apologised for the phrase "Allahu Akbar" being shouted at the beginning of an anti-terror training exercise in Manchester. Assistant Chief Constable Garry Shewan from Greater Manchester Police said: "The scenario for this exercise is based on a suicide attack by an extremist Daesh-style organisation. "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." Greater Manchester's Mayor and Police and Crime Commissioner Tony Lloyd said: "This was a very good exercise in preparing for a situation we never want to see, but must be ready for. "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 '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." The exercise began at midnight in the Trafford Centre when a man playing the part of a suicide bomber entered the crowded centre before pretending to detonate a bomb. Hundreds of volunteers played the role of shoppers, screaming in panic and fleeing while others collapsed on the ground covered in fake blood. The sound of gunfire was also heard rattling around the shops. Emergency services including counter-terrorism police, fire and ambulance crews - who had not been told the precise nature of the exercise - rushed to the scene as if they were dealing with a real event. Volunteers were assured no live rounds would be used and within minutes groups of armed police arrived and entered the centre while stepping over 'injured' members of the public. The exercise has been designed to appear as real as possible to allow officials to measure the response of emergency services in the event of a real terrorist attack in the UK. The Trafford Centre, which is the second largest shopping centre in the UK and attracts some 35 million visitors every year, is open for business as usual today. Similar exercises are expected to continue at undisclosed locations throughout the day.