LONDON — Greater Manchester police briefly asked the public to stay out of a neighborhood in the nearby town of Wigan on Tuesday as a bomb-disposal unit searched for explosives — part of the investigation into the attack that hit an Ariana Grande concert.
Grande, meanwhile, said she and other top stars — including Justin Bieber, Coldplay, and Miley Cyrus — will perform at a benefit concert in Manchester Sunday night, less than two weeks after bomber Salman Abedi killed 22 people at her Manchester Arena show.
Police trying to unmask the network behind Abedi searched a property in Wigan, 20 miles northwest of Manchester, and placed a security cordon around the neighborhood for several hours.
But London’s Metropolitan Police said Tuesday that military support for the counter-terrorism operations is gradually being reduced now that the official threat level has been lowered from ‘‘critical’’ to ‘‘severe.’’
Assistant Commissioner Mark Rowley said ‘‘military personnel will remain in readiness to support the police, should it be necessary.’’
Officials also said extra police staffing that had been added to protect public gatherings over the holiday weekend would be reduced.
The railway station next to Manchester Arena, which had been shut since the blast, reopened Tuesday.
Manchester Mayor Andy Burnham and Transport Secretary Chris Grayling were among those who laid wreaths at Victoria Station, which also suffered damage in the blast.
Burnham said the city had pulled together ‘‘through what has been our darkest week.’’
The return to a level of normalcy followed days of emotional tributes to the Manchester attack victims. Hundreds stood in quiet contemplation at St. Ann’s Square, where a sea of cards, flowers, and balloons has grown into an impromptu memorial site.
Police are trying to recreate attacker Abedi’s movements before he detonated a bomb at the concert and are trying to track a blue suitcase he was seen with in closed-circuit TV footage.
Fourteen men have been arrested, most in and around Manchester, and police have scoured more than a dozen properties as investigators piece together the network around Abedi, a 22-year-old Briton of Libyan descent. He died when the bomb he was carrying in a knapsack exploded among the concert crowd.
The 14 men under arrest have not been identified or charged. Abedi’s older brother Ismail is reported to be among them, and his father and younger brother have been detained in Libya.
British officials are under pressure to explain how Abedi was able to carry out his plot undetected. The government has said he was one of thousands of people peripherally on intelligence agencies’ radar but was not a focus of surveillance.
Manchester’s police chief said Abedi had come to the attention of police for ‘‘relatively minor matters’’ including theft, receiving stolen goods, and assault. But Chief Constable Ian Hopkins said Abedi had not been known to the government’s counter-radicalization program, known as Prevent.