Manchester terror attack: UK Prime Minister May reduces threat level to 'severe'

Manchester Suicide Bomber Salman Abedi: A Timeline of Terror

Investigators are piecing together recent events in Salman Abedi’s life that led to the Manchester Arena suicide bombing attack that killed 22 people. Here’s what we know so far

British Prime Minister Theresa May announced Saturday that the country’s terrorist threat level has been reduced from “critical” to “severe.”

The change means another terrorist attack is highly likely, rather than imminently expected.

May, who returned early from the G-7 summit in Sicily, said major progress has been made in the investigation into Monday’s bomb attack in Manchester, which killed 22 people, but that people should remain vigilant.

Soldiers deployed to patrol Britain’s streets after the threat level was raised will gradually be withdrawn, beginning Monday, May said.

Until it was raised Tuesday, the terrorist threat level had stayed at severe for three years.

Police arrested two more suspects – aged 20 and 22 – early Saturday in the northwest England city on suspicion of terrorism offenses. Police used an explosive device to get into a property to make the arrests.

Greater Manchester Police said they are now holding 11 men, aged between 18 and 44, in custody and have made major progress in their investigation.

Mark Rowley, Britain's top counterterrorism police officer, said authorities have dismantled a "large part" of the network around bomber Salman Abedi. But he said there were still "gaps in our understanding" of the plot, as investigators probed Abedi's potential links to jihadis in Britain, Europe, Libya and the Middle East.

Hundreds of soldiers have been sent to replace police at high-profile sites including Buckingham Palace and Parliament, and police armed with submachine guns are being deployed in city centers, transit hubs, tourist areas and major events.

Despite the critical alert, police have urged people to go out and enjoy themselves over the three-day holiday weekend. More than 1,000 armed police are on standby as major events including the Football Association Cup Final and the Premiership Rugby Final are expected to draw tens of thousands of people.

Manchester is slowly returning to normal, though dozens of people remain hospitalized and the damaged arena and adjacent Victoria train station remain closed.

Grande has promised to return to Manchester for a benefit concert. In a statement Friday, she said "I'll be returning to the incredibly brave city of Manchester to spend time with my fans and to have a benefit concert in honor of and to raise money for the victims and their families."

"Our response to this violence must be to come closer together, to help each other, to love more, to sing louder and to live more kindly and generously than we did before," she said. "We will not quit or operate in fear. We won't let this divide us. We won't let hate win."

The Associated Press contributed to this report.