Police have been given more time to question four men arrested on suspicion of committing terrorism offences.
Two men from London, aged 22 and 23, a 21-year-old man in Manchester and a 19-year-old man in Peterborough were detained in raids on Monday morning.
They were held on suspicion of the commission, preparation or instigation of a terrorist act. Police now have until 6 January to question them.
A 19-year-old man also arrested in Peterborough has been released on bail.
He was held on suspicion of encouraging terrorism. Police have until late January to carry out their inquiries.
Officers are continuing to search a number of properties.
The arrests, which were part of a planned operation, were not linked to the attack at Fishmongers’ Hall in London.
Separately, a 21-year-old man arrested on 28 December in east London, on suspicion of the commission, preparation or instigation of an act of terrorism, has been released without charge.