The hunt is still on for suspects in the Manchester bombing, and members of attacker Salman Abedi’s network may still be at large, Britain’s interior minister said Sunday.

“The operation is still at full tilt,” Home Secretary Amber Rudd said. Police say that 1,000 people are working on the investigation, trying to track down bomber Salman Abedi’s accomplices and piece together his movements in the days before the attack.

“Until the operation is complete, we can’t be entirely sure that it is closed,” Rudd said.

Abedi, a 22-year-old Briton of Libyan descent, killed 22 people and himself on May 22 at an Ariana Grande concert. Police have 11 suspects in custody — including Abedi’s elder brother Ismail — and have searched properties across the northwest England city. Another brother and Abedi’s father have been detained in Libya.

On Saturday, Britain lowered its official terrorism threat level from “critical” to “severe” after police said they had dismantled a large part of Abedi’s network.

Police have released surveillance-camera images of Abedi on the night of the attack and appealed for more information about his final days. They say he returned to Britain from Libya on May 18, and likely completed assembling his bomb at a rented apartment in central Manchester.

The images show Abedi in the hours before the attack, wearing sneakers, jeans, a dark jacket and a baseball cap. The straps of a knapsack are visible on his shoulders.

Security remained high at major events across Britain on Sunday, including the Great Manchester Run road race, where police armed with submachine guns protected participants and spectators.

The government is facing criticism after acknowledging that Abedi was on security services’ radar, but wasn’t a major focus of investigation.

Rudd said Sunday that intelligence agencies were monitoring 3,000 suspected extremists and had a wider pool of 20,000 people of interest.

“I would not rush to conclusions … that they have somehow missed something,” Rudd said.

The family of one victim, 18-year-old Georgina Callander, said her life had been cut short by “evil, evil men prepared to ruin lives and destroy families.”

“I wish I could say that Georgina is one of the last to die in this way but unless our government opens its eyes we know we are only another in a long line of parents on a list that continues to grow,” the family said in a statement released through Greater Manchester Police.

(AP)