Britain's terror threat level has been reduced to "severe" from "critical", UK Prime Minister Theresa May said Saturday after meeting with security chiefs.
She said "significant activity" by the police during the last 24 hours led to the threat being reduced. "A threat level of severe means an attack is highly likely", she said.
"The compassion, kindness, love, strength and oneness that you've shown one another this past week is the exact opposite of the heinous intentions it must take to pull off something as evil as what happened Monday", she said. Police searched the building and found nothing suspicious.
Operation Temperer, which has seen armed soldiers support police on the streets, will be gradually stood down after the bank holiday weekend.
These can't be directly linked to Monday's bombing, Chief Constable Ian Hopkins said, but police are monitoring the situation.
"As part of the ongoing investigation into the attack on Manchester Arena, two men aged 22 and 20 have been arrested on suspicion of offences contrary to the terrorism act", a Greater Manchester Police statement said.
May said this meant the independent body which sets the threat level had decided it should be lowered from its highest rating "critical", which meant an attack could be imminent, to "severe".
The opposition Labour Party, emboldened by a rise in opinion polls, argued that Britain's foreign policy had increased the risk of attacks and criticised Conservative Prime Minister Theresa May for cutting spending on policing.
"The understanding of [the plot] is growing day by day", Britain's top counterterror officer, Assistant Commissioner Mark Rowley, said Friday. Many suffered "horrific" and potentially life-changing injuries, a senior doctor said.
In the latest police action, officers used a controlled explosion to gain entry to an address in the north of the city where two men were detained on Saturday.
Residents were evacuated from streets in the south Manchester neighborhood of Moss Side in what police called a precaution as one search was carried out Saturday.
Investigators have searched 17 properties, including bomber Salman Abedi's home in south Manchester and other houses in nearby districts. A total of 116 people were treated in hospitals after the bombing.
However, Assistant Commissioner Mark Rowley, the United Kingdom police chief for counter-terrorism, advised people to be vigilant but to "go out as you planned and enjoy yourselves".
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.
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.