LONDON, May 23 (Xinhua) -- British Prime Minister Theresa May said Tuesday that authorities are trying to establish the full details of the explosion at the Manchester Arena late Monday night that killed at least 19 people and injured dozens of others.

"We are working to establish the full details of what is being treated by the police as an appalling terrorist attack," she said in a statement. "All our thoughts are with the victims and the families of those who have been affected."