The Manchester bomber Salman Abedi is believed to have travelled to Syria and had “proven” links with Islamic State, France’s interior minister has said.
Gerard Collomb told French television that both British and French intelligence services had information that Abedi had been in Syria.
The disclosure came as Home Secretary Amber Rudd confirmed the UK security services had been aware of the British-born 22-year-old.
“We do know that he was known up to a point to the intelligence services,” she told Sky News.
“I am sure that we will get more information about him over the next few days and the next few weeks.”
Prime Minister Theresa May announced late on Tuesday that the terrorism threat level was being raised to “critical” - the highest alert level - meaning that an attack is thought be imminent.
The move reflects fears that a “wider group of individuals” may have been involved in the attack - including the bomb-maker who provided Abedi with his deadly device.
Following Monday’s blast at the Manchester Arena which left 22 dead and 59 injured, the Government has activated Operation Temperer, providing up to 3,800 troops to support the police in their security operations.
Ms Rudd said the move was temporary but refused to be drawn on how long the heightened state of alert would remain in place.
“It is an ongoing operation which means that the investigation is continuing to find leads,” she said.
“So until we can be reassured that there is no continued activity around this operation, that it is entirely safe around this operation, then it is right that we are at this heightened state of alert.
“It is operationally driven, it is intelligence-driven and we must make sure that we allow our counter-terrorist police, our police and our intelligence services to get on and do their job and this helps give them the space to do just that.”