Manchester attack: suicide bomber 'travelled by train to Victoria Station' before killing himself and 22 others

Police believe a suicide bomber travelled by train to Manchester’s Victoria Station and detonated an explosive device in the ticket area as concert goers were leaving after pop star Ariana Grande’s performance, according to reports today in the United States.

Quoting two US law enforcement sources who had been briefed on the tragedy, CBS News said the massacre was the work of a lone bomber.

The US network said ball bearings - thought to have been used to make the bomb - had been recovered and detectives were piecing together the bomber’s movements through CCTV footage.

Body parts of the suicide bomber have been recovered, said CBS.

A source also claimed one person was detained in a vehicle but it is not clear what, if any, involvement that potential suspect may have had in the incident.

US officials told NBC News that initial reports indicated that some of the casualties might have been caused by a stampede of concert-goers.

White House Press Secretary Sean Spicer said President Donald Trump's national security team was keeping the president up to date while he is in Israel.

The US Department of Homeland Security stressed that there was no information to indicate a specific credible threat involving American music venues.

Ivo Delgado, who attended the event, told NBC News that the concert had just ended when 'I just heard a loud bang. People started screaming and going to the other side of the arena," said Mr Delgado, who said he saw at least one person with blood on his face.

Catherine Macfarlane described it as a 'huge explosion.'

'You could feel it in your chest. It was chaotic. Everybody was running and screaming and just trying to get out,’ she added.

Zach Bruce, who was at the concert, described the scene on the phone to CBSN, saying: 'It was one loud bang -- it was so loud,’