British police arrest four suspects in anti-terror raids on Sheffield and Chesterfield

London: British counter-terror officers arrested four persons on suspicion of plotting terror attacks in the UK, officials said.Three of them, aged 22, 36 and 41, were arrested from Sheffield and the fourth man, aged 31, from Chesterfield by counter-terrorism officers in an operation led by the North East counter-terrorism unit."The arrests were intelligence-led and pre-planned as part of an ongoing investigation by Counter Terrorism Policing North East," a West Yorkshire Police spokesperson said."We recognise that local people may have concerns as a result of this activity. We would ask people to remain alert but not alarmed and we are grateful for the assistance and understanding of people locally," he said.All four men have been detained on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism under the UK's Terrorism Act 2000.The men were being questioned at a police station in West Yorkshire while property searches where they were arrested continue.People reported the sound of an explosion as police raided an address in Meersbrook, Sheffield. "The public may have heard a loud bang at the time as police entered one of the properties, but it was not an explosion.They (officers) would like to reassure them that it was part of the method to gain entry to the property," the police spokesperson added.