British Foreign Secretary Boris Johnson, left, and U.S. Secretary of State Rex Tillerson at a news conference in London on May 26, 2017. (Adrian Dennis/AFP/Getty Images)

Britain’s top counterterrorism official said Friday that authorities believe they have rounded up most of the network suspected of involvement in Monday’s terrorist bombing in Manchester, but the country remained braced for further violence ahead of a sunny long weekend packed with road races, soccer matches and other ripe targets.

The announcement eased worries from earlier in the week that the sophistication of the suicide blast that killed 22 people meant that a bombmaker could still be on the loose with further attacks planned. But authorities still cautioned vigilance, and more than a thousand soldiers remained deployed across Britain, an unusual measure in a country where few police officers carry firearms.

“We’re very happy we’ve got our hands around some of the key players that we’re concerned about,” said Assistant Commissioner Mark Rowley, the head of National Counterterrorism Policing at the Metropolitan Police. He said investigators were trying to unravel 22-year-old Salman Abedi’s life and also to reconstruct his final days and hours.

British Home Secretary Amber Rudd on Friday kept the country’s threat level at “critical,” the highest state of alert, leaving in place 1,000 troops who have been deployed to Britain’s streets to supplement the police. The security alert indicates authorities believe new attacks are imminent.

[Manchester bombing probe reaches across two continents]

(Sarah Parnass/The Washington Post)

But top officials said they had no specific knowledge of threats during the upcoming weekend. Monday is a holiday in Britain. Authorities said they were keeping an eye on more than 1,300 public events over the weekend, including a series of sporting events across Manchester.

There were signs of the strain on Britain’s diverse society, as Greater Manchester Police Chief Constable Ian Hopkins said that reports of hate crimes in the city after the Monday-night attack had doubled between Monday and Wednesday.

In an early-morning raid on a barbershop in the Moss Side neighborhood of the city, police on Friday arrested a 30-year-old man, bringing to nine the number of people in custody. Their ages ranged from 18 to 44. An additional two people were detained, then released, this week. Part of Abedi’s family lives in Libya, and several members, including his father and brother, were also in custody there.

Police also raided an apartment building in Manchester’s city center where Abedi is thought to have rented a $97-a-day flat in the week ahead of the attack and where bomb-making materials were found after Monday’s explosion. British media reported that enough nuts, bolts and chemicals were discovered there to construct another bomb. Local journalists reported Friday that forensics teams were again searching inside the building and in garbage bins outside.

[Signs of the Manchester attacker’s possible radicalization appeared a year ago]

The raids came as top U.S. and British officials tried to patch a significant rift that had opened between normally close intelligence agencies. Leaks, apparently from U.S. authorities, prompted an unusual public rebuke from British Prime Minister Theresa May.

Visiting London on Friday to offer condolences after the attack, Secretary of State Rex Tillerson said that the close relationship between U.S. and British intelligence agencies would survive the strain of the disclosures.

The rare dispute with Washington’s closest intelligence partner flared Thursday when police authorities in Manchester briefly interrupted information sharing with their American counterparts.

The cooperation later resumed after President Trump assured May that he would crack down on leaks.

“We take full responsibility for that, and we obviously regret that that happened,” Tillerson said after a lunch meeting with British Foreign Secretary Boris Johnson at the British diplomat’s London residence. “This special relationship that exists between our two countries will certainly withstand this particular unfortunate event,” Tillerson said.

“All across America, hearts are broken” about the victims of the bombing, Tillerson said.

Johnson played down any lasting rift between British and American intelligence authorities, praising the “vital importance” of work between U.S. and British authorities, including intelligence sharing.

“Around the world you will find the U.S. and the U.K. facing the same problems together,” Johnson said.

Trump called on the NATO defense alliance Thursday to focus on “immigration” as a security threat, a remark that seemed at least partly targeted toward Abedi, a British-born son of immigrants from Libya.

Tillerson said that during Trump’s nine-day international trip that concludes Saturday, the president had repeatedly raised the issue that “for whatever reason, as people immigrate into our countries, whether it be in Great Britain or in the United States or other countries, we seem to have difficulty assimilating those people so that they feel part of our society and would never consider supporting acts of violence against their fellow citizens and their fellow neighbors.”

[Why Britain’s government doesn’t leak the way America’s does

May buttonholed Trump on Thursday about keeping information from British investigations private. Some of the most important developments in the Manchester case were first made public by U.S. media outlets, which cited U.S. officials as sources.

The flare-up between the two nations was in part a reflection of their starkly differing cultures of leaks and media freedoms.

U.S. media outlets have a long history of publishing leaked intelligence, typically justified by the idea that a maximum amount of transparency helps inform the public about the actions and calculus of government agencies, so long as publishing does not directly endanger lives. Press freedoms are enshrined in the Constitution.

In Britain, however, media outlets have no such legal rights. They have been more deferential to official requests to withhold the publication of sensitive information — and are subject to prosecution if they ignore the demands.

Read more:

Trump calls for investigation of U.S. leaks in Manchester bombing probe

Manchester, a city that’s been knocked down before, vows to get back on its feet

‘We had to pull nails out of children’s faces’: Homeless men helped after Manchester blast

Today’s coverage from Post correspondents around the world

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