Security has been increased in public places around the UK after a terrorist attack on a pop concert in the city of Manchester.
22 people died and around 60 were seriously injured in a terrorist bombing at the end of a concert by American singer Ariana Grande at the Manchester Arena on Monday night. The bomber died in the blast, and police have arrested another man.
It was the worst terrorist attack in the UK for 12 years, and there have been many messages of support, including from many world leaders and the Queen.
London's police chief says there will be extra armed police officers on the streets for as long as they are needed, and there are safety discussions with organisers of events happening this weekend.
Sarah Cooper, the chief executive of English UK, said: "We are shocked and distressed by this attack on people who were enjoying a night out, and our thoughts are with the families of those involved.
"English UK member centres are serious about protecting our students, and will be carefully monitoring the situation as part of their ongoing risk assessments.
"Our accredited centres have the strictest regulations in the world on looking after under-18s and keeping them safe, and will also be advising adult students and keeping them informed. We would like to reassure students, their families, and agents that in general the UK is a very safe destination."
The concert's audience included many families and teenagers, and ordinary people in Manchester helped them by sheltering them in their homes and hotels, or by driving them home. Many taxi drivers worked free during the night.
Andy Burnham, the Greater Manchester mayor, thanked the emergency services for their work and added: "I wanted to thank the people of Manchester. Even in the minutes after the attack, they opened their doors to strangers and drove them away from danger. "They gave the best possible immediate response to those who seek to divide us and it will be that spirit of Manchester that will prevail and hold us together."