Police hunting a suspected network behind Salman Abedi, the bomber who killed 22 people on Monday night, said they had made two further arrests overnight and that they had a greater understanding of how his device was made.
She said: "The public should be clear about what this means - a threat level of severe means an attack is highly likely".
Police have 11 suspects in custody - including Abedi's elder brother Ismail - and have searched properties across the northwest England city.
Manchester-born Abedi likely received some ISIS training in Syria in the months before the attack, according to information gathered in the preliminary investigation, a U.S. official told CNN on Thursday.
In the latest police action on Saturday, officers used a controlled explosion to gain entry to an address in the north of the city where two men were detained. The troops will gradually be withdrawn from Monday, May said.
Investigators believe 22-year-old Manchester-born suicide bomber Salman Abedi, from a family of Libyan origin, acted as part of a terrorist network and their focus had been on intercepting his wider network.
A 16-year-old boy who had been arrested has been released without charge, police said.
A bomb disposal unit stops outside a street in Moss Side, Manchester.
Manchester City Council's executive member for culture and leisure, councillor Luthfur Rahman, said earlier this week: "Manchester is a truly resilient city and we look forward to successfully hosting these great sporting events, with the support of Greater Manchester Police".
Abedi spent time in Libya before the attack and transited through Istanbul and Dusseldorf airports on his way back to Britain.
Speaking ahead of the run, Mr Burnham told reporters: "It was a hard decision and we took advice from the police and the security services". Mohammed El-Hudarey, a friend of the landlord, said after Abedi moved out about six weeks ago there was a strong smell of chemicals and debris including metal rods and cut-up fabric.
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.
Britain's health service said Saturday that 63 people injured in the bombing remain hospitalized, 20 of them in critical condition.
She goes on to say: "We will not quit or operate in fear".
Manchester is slowly returning to normal, though the damaged arena and adjacent Victoria train station remain closed.
"After everything that's happened in Manchester, to get everyone to come together, stand united, don't let them win, that's why I'm doing it", runner Ian McLellan, 45, told AFP.
Several key details about the investigation into the Manchester terrorist attack were leaked to the news media by USA officials. As the investigation continues, authorities have said that they are certain they now know the names of all the victims.
A game of football or a concert is a moment that you must live with passion and enthusiasm. "I just want to enjoy my football". He can think what he wants. "For this reason, I hope to see a great game and all my players trying to win for us", Conte said.
Terry experienced his first FA Cup final as an unused substitute in Chelsea's win over Aston Villa in 2000. This aspect I can stay calm and I trust the players, it is impossible not to after this season .
More than two thirds, 68 percent, said that Russian interference in the election is "very important" or "somewhat important". According to the survey, the president's job approval rating declined to 45 percent now from 49 percent in March.
In light of that need for roster enhancement, this could have been the last parquet party for a fair number of those in uniform. The deficit reached a peak of 37 points, the second worst under Brad Stevens to the 50-point lead the Cavs reached in Game 2.
Short is Exeter's top try-scorer this season, scoring 11 tries in the Premiership and going over 14 times in all competitions. The game also marked England worldwide Danny Cipriani's return to Wasps after he rejoined from Sale Sharks over the summer.
Trump is expected to become the first sitting U.S. president to visit the Western Wall , the holiest site where Jews can pray. His nine-day trip through the Middle East and Europe ends on Saturday after visits to the Vatican, Brussels and Sicily.
He also added eight rebounds, eight assists and three steals as the Cavs romped to a 135-102 victory and a 4-1 series win. LeBron and Kyrie combined for 28 third-quarter points, with Irving going for 13 points and four assists in the frame.
The awkwardness may stem from Trump's tacit support of Macron's rival Marine Le Pen during the French election. President Macron said he respected President Trump's decision to put the Paris agreements under review.
Showing all of his class and experience, Oracle skipper Jimmy Spithill refused to give in and gradually clawed his way back. Crewmen on SoftBank Team Japan had to leap clear of Ainslie's port hull as it crashed onto their starboard hull.
Cavs beat Celtics to earn NBA Finals rematch with Warriors
James had earlier been whistled for his fourth foul with nearly seven minutes left in the first half, sending him to the bench. The Cavaliers outscored the Celtics 65-42 in the second half, thanks to Irving's playoff career high in points.
Intel spat adds to Israeli concerns about Trump visit
The wall is in the Old City, a part of east Jerusalem , which the US and most of the world consider to be occupied territory. Trump said as a candidate he would move the embassy to Jerusalem , but now says he's studying the issue.
JEE Advanced tomorrow, more than 2500 to appear in Odisha
The previous year, many students and teachers said that components of the JEE (Advanced) were particularly challenging. The paper contained a mix of single choice, multiple correct choice and passage type single choice question.
4 militants killed in Rampur sector: Army
Indian army Tuesday claimed it had damaged some Pakistani army posts on LoC and described it as "punitive fire assaults". Two groups of terrorists managed to cross the LoC even during winter when the mountain passes were covered with snow.
Steven Mnuchin at G7: 'We don't want to be protectionist'
Another senior official from the delegation said, "Each one of us is following developments in USA tax policy very closely". The aim for the G7 and central bankers on Saturday is to join forces to fight the growing threat of worldwide cyber attacks.
With budget unfinished, Legislature heads to special session
There were other complications with the one-page special session agreement hurriedly drafted Monday among the state's top leaders. On Wednesday, the House approved bills for taxes, education and transportation, with senators doing the same with taxes.
A Warm Memorial Day Weekend, Could See Some Rain
MEMORIAL DAY MONDAY: Partly cloudy skies will develop for Memorial Day Monday, with a high temperature of 79 degrees. New rainfall amounts between a tenth and quarter of an inch, except for higher amounts possible in thunderstorms.
British police say military to guard key London sites
Sixty-four people are still hospitalized, Jon Rouse of the Greater Manchester Health and Social Care Partnership said Wednesday. France, which has repeatedly been hit by devastating militant attacks since 2015, extended emergency powers.