Anti-terror police have been granted more time to question four people who were arrested under the Terrorism Act at Manchester Airport.
Two men, aged 48 and 23, and two women, aged 48 and 27, were detained by armed officers early on Monday, and are now being quizzed in Greater Manchester.
They are being held on suspicion of providing money or other property suspected of being used for terrorism.
Anti-terror police now have until 1630 BST on Friday to question the suspects.
Following the arrests at Manchester Airport, officers from Greater Manchester and West Midlands Police later raided a house in Dudley, in the West Midlands.
The operation is the latest move in the UK-wide fight against terror following the bombing atrocities in London last month, but it is not thought connected with the investigation into the attacks on the capital.
On 27 July, terror suspect Yasin Hassan Omar was subdued with a 50,000 volt Taser and arrested by police when they stormed a ground-floor flat in Hay Mills, Birmingham.
Omar, 24, of Arnos Grove, north London, was detained in connection with the failed 21 July bus and tube attacks in London.
He has since been charged with attempted murder and explosive offences and remanded in custody.