People in Manchester, England, gather in St. Ann's Square on Thursday, May 25. They were observing a national minute of silence to remember the victims of a suicide bombing at an Ariana Grande concert. Jeff J Mitchell/Getty Images

Britain's Queen Elizabeth II speaks to 15-year-old Millie Robson and her mother, Marie, during a visit to the Royal Manchester Children's Hospital on May 25. The Queen was visiting those injured in the attack. Peter Byrne/WPA Pool/Getty Images

A police officer guards a house in Manchester as investigations continued on May 25. Police say a man carrying explosives acted as a lone attacker and died in the blast. JON SUPER/AFP/Getty Images

Flowers and tribute messages are left for victims in St. Ann's Square. OLI SCARFF/AFP/Getty Images

A women sheds tears after observing the minute of silence in St. Ann's Square. JON SUPER/AFP/Getty Images

A Manchester road is closed off as police raids continued on May 25. Christopher Furlong/Getty Images

Local residents hold Manchester City and Manchester United soccer jerseys during the national minute of silence. Christopher Furlong/Getty Images

Police officers deliver flowers to a makeshift memorial in Manchester on Wednesday, May 24. Leon Neal/Getty Images

Women cry after placing flowers in Manchester on May 24. Emilio Morenatti/AP

A forensics team works at the scene of the explosion on Tuesday, May 23. Dave Thompson/Getty Images

British Prime Minister Theresa May condemns the "callous terrorist attack" as she delivers a statement in London on May 23. DANIEL LEAL-OLIVAS/Getty Images

Police help someone after the attack at Manchester Arena on Monday, May 22. Joel Goodman/LNP/REX/Shutterstock

People gather outside the arena. "We can confirm there was an incident as people were leaving the Ariana Grande show last night," police said on Twitter early on Tuesday. "The incident took place outside the venue in a public space. Our thoughts and prayers go out to the victims." MCPIX/REX/Shutterstock

People receive medical attention at a railway station close to the arena. The incident happened shortly after Grande had left the stage, shortly after 10:30 p.m. (5:30 p.m. ET) according to eyewitnesses. Calvin Welsford, an 18-year-old concertgoer, said that he heard a "loud bang" a couple of minutes after Grande's set had finished. Dave Thompson/Getty Images

Paramedics respond to the scene. PAUL ELLIS/AFP/Getty Images

Emergency workers and concert attendees gather outside the arena. Peter Byrne/PA Wire/AP

People stand by a cordoned-off street close to the arena. Dave Thompson/Getty Images

Greater Manchester Police tweeted that emergency services were "responding to (a) serious incident at Manchester Arena. Avoid the area. More details will follow as soon as available." Joel Goodman/LNP/REX/Shutterstock

People are escorted away from the arena. Dave Thompson/Getty Images

People sit outside near the arena. The crowd was made up of mainly younger people who had come to see Grande in her first of three scheduled concerts in the UK. Joel Goodman/LNP/REX/Shutterstock

An injured man is helped at the scene. Joel Goodman/LNP/REX/Shutterstock/