Police have been given more time to question three people arrested on suspicion of terrorism offences after a series of raids across England.
Some homes are still being searched
The three are being held under the Terrorism Act following raids on 19 addresses on Wednesday.
Five other people are still being held under immigration legislation.
More than 500 officers took part in raids of properties in Manchester, Liverpool, Middlesbrough, Bolton, Birmingham and London.
The operation involving five police forces was headed by Greater Manchester Police.
A spokeswoman for the force said detectives had been given more time to question the three people held under anti-terrorism legislation.
She said police were continuing to search six addresses in Manchester and one in Middlesbrough.
The other five men are being held under the Home Secretary's powers to deport individuals whose presence in the UK is "not conducive to the public good for reasons of national security".
The eight detained men are reported to be Libyans and the operation was aimed at those suspected of aiding attacks on targets in Iraq.
One of the men arrested in Manchester was Libyan-born Tahir Nasuf, a 44-year-old who moved to Manchester in 1993 and is married with four children.
The offices of a charity he works for - the Sanabel Relief Agency - were also raided in Birmingham.