Greater Manchester Police has stressed that "significant progress" is being made in their investigation
A 38-year-old man has been arrested at Heathrow Airport in connection with the Manchester Arena terror attack.
Police said the man is being held on suspicion of terror offences as part of a planned operation.
There was no direct threat to the airport during the arrest, they added.
A total of seven men remain in police custody in relation to last month's suicide bombing, which killed 22 people at a pop concert in Manchester Arena.
Police have said that the bomber may have stored items used to make the bomb in a Nissan Micra, adding that "significant evidence" was found in the white car.
The vehicle was seized in Rusholme on Friday.
The car, which had an "R" registration plate, had been sold by its previous owner in April - two days before bomber Salman Abedi had left the UK to go abroad.
Investigators say it is "vital" they understand what happened to the car between 13 and 15 April, as it could help them identify who used the car and where it went.
Detective Chief Superintendent Russ Jackson said: "We know Abedi bought some of the parts of the device after landing back in the UK and although his final acts on the night seem to have been alone, this doesn't mean that he did not have support in planning this attack.
"It is vital we exhaust all our lines of enquiry to establish how this was planned and understand how others might have been involved."
Twelve people arrested during the massive operation that followed the bombing have since been released without charge.
On Tuesday an 18-year-old man - understood to be a cousin of Abedi - was freed along with two other men.
Abedi's brother Ismail, 23, was released on Monday, while his other cousins, Isaac Forjani, 24, and Abz Forjani, 21, both from Fallowfield, Manchester, were among those released last week.
Greater Manchester Police has stressed that "significant progress" is being made in their investigation.
Meanwhile, police investigating Saturday night's terror attack in London said on Wednesday that they had arrested a 30-year-old man on suspicion of terror offences in Ilford, east London.
Additional reporting from IRN