A property in Manchester is also being searched
A 19-year-old man has been arrested in Britain at Liverpool John Lennon Airport in connection with the Manchester Arena bombing.
He was arrested on suspicion of offences contrary to the UK's Terrorism Act and remains in custody, Greater Manchester Police said.
A property in Manchester is also being searched as part of the investigation.
Twenty-three people have now been arrested over the May 22nd suicide bombing.
Two were quickly freed and 20 others were released without charge.
Salman Abedi's attack killed 22 people as people streamed out of the Ariana Grande concert.
Police said earlier this week that they still want to speak to Abedi's brother, and that they believe "other people" may have been involved.
Chief Superintendent Russ Jackson said he did not believe it was a "large network" that was involved in the bombing.
"We don't have evidence that there were other suicide bombers, we do suspect others were aware or complicit in their knowledge of the attack," he said.
"We do believe there may be other arrests in the future."
Three million files and 16,000 hours of CCTV have been collected as police have sought to detail Abedi's movements in the days and weeks before the attack, and establish any terrorist connections he may have had.