- Video report by ITV News security editor Rohit Kachroo
Police have "got hold of a large part" of the terror network behind the Manchester bombing, Britain's most senior counter-terrorism officer has said.
Assistant Commissioner Mark Rowley said detectives had made "immense" progress in the investigation with "key players" thought to have been identified.
However, he warned there were still "important" lines of inquiry to pursue, with further arrests likely.
Nine men are currently in custody, all aged between 18 and 44 and all arrested on suspicion of terrorism offences. A 16-year-old boy was released without charge.
"Even with all the progress made so far, there still remain important lines of enquiry that will further build our confidence and understanding of the events that led to this ghastly attack," he said.
Mr Rowley also urged people not to change their plans in the wake of the attack.
Police have reviewed security at more than 1,300 events across the country, he said.
He also asked that anybody who sees anything suspicious over the coming days to alert police immediately.
"My request to the public is simple - if this weekend you see something out of place, that causes you concern or raises your suspicions, tell us," he said.
"If you have those suspicions now about someone - tell us - we will act on all information we are given and together we can defeat terrorism."