Armed police officers stand near the Manchester Arena, where American singer Ariana Grande had been performing. Photo: Reuters / Andrew Yates

At least 19 people were killed and dozens injured in a suspected terror attack at a pop concert in Manchester, Britain, on Monday evening.

Police reported that 19 people had been confirmed dead following an explosion at Manchester Arena, where the American singer Ariana Grande was performing in front of some 21,000 fans. A further 50 people were injured, the police said.

The blast was reported to have hit the foyer of the building at about 10:30pm. Manchester Arena said the incident took place “outside the venue in a public space.”

Areas around the arena were immediately sealed off and the city’s Victoria Station has been closed.

British Prime Minister Theresa May said her thoughts were with the victims and families of those affected in “what is being treated by the police as an appalling terrorist attack”.