Washington (CNN)Salman Abedi, the 22-year-old alleged Manchester bomber, traveled to Libya for three weeks, returning to the UK only days before launching his attack, according US military officials assigned to Africa Command.
That specific information has been shared between US and British intelligence services, the US officials said, adding they currently have "high confidence" the information is accurate. But they also caution a full intelligence analysis is underway, including trying to determine Abedi's communications. Any new information could change the current view.
All of this is raising questions about Abedi's travel route and how aware British authorities were of him and his movements in recent weeks. The US officials say it's possible Abedi could have traveled from the UK to a nearby country such as Tunisia, which perhaps would not have raised the same red flags as a direct route.
It's relatively easy to cross the Libya-Tunisia border over land. It's also possible to travel via commercial air routes into Libya from a UK departure point.
It also raises questions about what he was doing there, whom he met with and whether he received training or support. Africa Command, which oversees any US military involvement in Libya and has extensive contacts with government and militia groups there, is now trying to use those contacts to learn where Abedi went and who he might have met with, the US military officials said. Abedi is believed to have family members still in Libya, but so far, the US has not been able to determine where they are.
US and UK intelligence services, along with Africa Command, are looking at the possibility Abedi could have met with ISIS members or operatives from al Qaeda in the Islamic Maghreb (AQIM).
AQIM and ISIS both are estimated to have hundreds of fighters in Libya, but ISIS in recent months has been pushed south and is struggling to regroup. AQIM is believed by the US to be mainly in south western Libya and trying to regain a higher profile after months of international attention being paid to ISIS, the officials said.
Manchester unites: We're stronger together 01:39
Known to authorities
Abedi was already known to authorities, UK Home Secretary Amber Rudd said Wednesday. But it's not yet clear why he was on their radar.
"The intelligence services know a lot of people, and I'm sure we will find out more what level they knew about him in due course," she told the BBC.
"But at the moment, all they have confirmed is that they did know about him, and as I say we will find out more when the operation is complete."
Abedi is believed to have died in the powerful blast outside an Ariana Grande concert in Manchester, though he has not yet been formally identified by the coroner, Manchester police said.
But Rudd told the BBC that Abedi -- who she said had recently returned from a trip to Libya -- may not have worked alone.
