While most of Britain prepared for bed, a potential terrorist attack struck the city of Manchester Monday night. Details are still thin, but here's what we known so far:
The basics
At least 19 people have died and as many as 50 were hurt.
As people were leaving a concert by US pop star Ariana Grande at the Manchester Arena, loud explosions were heard outside the main area.
Many of Grande's fans are teenage and pre-teen girls (they call themselves the Ariana Army), so there would've likely been a lot of young people in attendance.
The initial reports of an explosion first came in at about 10:35 p.m. local time, according to Manchester police.
Local authorities are encouraging people with concerns or information to report them to an anti-terrorist hotline. They also have an emergency number for those concerned about loved ones -- +44 (0)161 856 9400.
The singer is OK. Her management have released a statement saying "we mourn the lives of children and loved ones taken by this cowardly act."
Grande tweeted: "broken. from the bottom of my heart, i am so so sorry. i don't have words."
Two explosions
Witnesses told CNN they heard one explosion near the arena. The blast occurred in a "public area" outside the venue, the Arena said in a statement.
There haven't been any claims of responsibility, but authorities are investigating if it was a suicide attack. A man who was at the scene has been identified as the possible attacker.
After the initial explosion, Manchester police said they conducted a precautionary controlled explosion in nearby Cathedral Gardens to destroy what turned out to be discarded clothing.
Victims and concertgoers
Police said 59 casualties were transported to six hospitals across Manchester, one of the UK's largest cities.
"After the first wave of sirens and the evacuation, it was filled with cars. The roads were bedlam. People just going through red lights," said Sam Ward, who lives near the arena.
The hashtag #RoomForManchester began trending as a way for locals to offer shelter or transport to those who needed it.
Facebook has activated its "Safety Check" feature.
The scene
Images quickly flooded the internet following the blast.
A dashcam caught the explosion from afar.
What's next for Britain
British Prime Minister Theresa May said in a statement that authorities "are working to establish the full details of what is being treated by the police as an appalling terrorist attack."
She will chair a meeting of the government's emergency Cobra committee early Tuesday morning.
May has suspended her campaign and the Scottish National Party has postponed the launch of a campaign manifesto. The United Kingdom is set to hold a general election on June 8.
Manchester links to radicalism
The Manchester incident comes nearly two months after an assailant killed five people outside Parliament in London, the first mass-casualty attack since the 2005 London bombings.
Police conducted a series of raids in Manchester -- which is home to a large and well-established Muslim population -- following that attack.
Earlier this year, Jamal Udeen al-Harith, a 50-year-old from Manchester, carried out a suicide bombing in Iraq on behalf of ISIS. While Pakistani national and Manchester resident Abid Naseer was convicted of a plot to bomb the city's central Arndale shopping center in 2015.
The attack also comes on the fourth anniversary of the killing of British solider Lee Rigby.
