'Key players' held as police make 'immense progress' in Manchester bomb probe
Detectives have made "immense" progress in the investigation into the Manchester bombing and are confident they have arrested some "key players", Britain's top counter-terror officer has said.
Assistant Commissioner Mark Rowley said police have made "significant" arrests and "finds" and have got hold of a "large part" of the suspected network being sought over the atrocity.
He said: "We are very happy we've got our hands around some of the key players that we are concerned about but there's still a little bit more to do."
The senior officer also issued a defiant message as he urged people to go about their business as normal over the bank holiday weekend.
"Enjoy yourselves and be reassured by the greater policing presence you will see," he said."We can't let the terrorists win by dissuading us from going about our normal business."
A huge security operation is planned with 1,100 armed officers on hand to protect major spectacles around the country, including the FA Cup Final at Wembley and the Great Manchester Run.
It was revealed that specialist teams have carried out a review of security for more than 1,300 events with Britain remaining at the highest threat level of critical while the investigation into the bombing continues.
Twenty-two victims including children were killed when Salman Abedi, 22, launched a suicide attack at an Ariana Grande concert at Manchester Arena on Monday night.
It was the worst terrorist atrocity to hit Britain since the July 7 attacks in London in 2005 and sparked a huge counter-terror probe.
Since Tuesday a total of 10 people have been arrested, with eight men aged between 18 and 38 remaining in custody. Two of those held, a 16-year-old boy and a woman aged 34, have been released without charge.
On Friday evening officers were still carrying out searches at 12 locations, with activity expected to continue throughout the weekend.
Providing an update on the probe, Mr Rowley said it was likely further arrests would follow.
"Having made enormous progress and made some significant arrests and had some significant finds, there still remain important lines of inquiry for us to pursue.
"We've got to try to understand everything we can about the dead terrorist, his associates. We need to understand the whole network and how they acquired and built the bomb that exploded on Monday night.
"It's going to take a little more time to close down those gaps in our understanding. We are working as fast as we can do because everyone wants answers to this."
He said police now have a "much better understanding" with a "lot of the risk contained". However, some uncertainty remains.
Mr Rowley said: "We need to grow our confidence that we have got every component of the network and we have got as full an understanding as possible about how the device was constructed and whether there's any remaining risk.
"Clearly we haven't covered all the territory we want to but we have covered a large part of it.
"Our confidence has been increasing over recent days but there's still more to do to get to the degree of confidence we want."
Mr Rowley outlined a number of strands of the investigation into the attack:
:: Finances - Officers are mounting a large-scale financial investigation, with Mr Rowley saying: "We are interested in equipment people have bought bearing in mind a bomb was constructed."
:: Communications - Police are looking back at communications and working closely with technology firms.
:: Exhibits - Investigators have seized large volumes of material during searches of a number of properties and expect to amass hundreds of electronic devices.
:: CCTV - Police are trawling through footage on local cameras to establish movements and patterns of activity in the lead up to the attack.
:: Witnesses - Officers are working to "triage" hundreds of statements from those caught up in the bombing.
:: International inquiries - Detectives are probing links to Libya as well as liaising with counterparts across Europe and elsewhere.
Meanwhile, further details about the scale of a wider terror threat emerged as figures indicated as many as 23,000 people have appeared on the radar of counter-terror agencies.
Authorities are handling 500 investigations into 3,000 individuals currently, while it was disclosed on Friday that around 20,000 people are considered former "subjects of interest".