Five men from Luton, have been arrested on suspicion of the commission, preparation or instigation of acts of terrorism.
The arrests were part of a "pre-planned, intelligence-led" operation by the Metropolitan Police counter-terrorism command.
The men, aged 21, 23, 24, 25 and 30, were all arrested at separate homes in Luton this morning and have been taken to a central London police station for questioning.
The raids took place at 7am involving scores of police.The arrests came after an intelligence gathering operation over the last few weeks.Arrests took place at five addresses in Luton.
The addresses were in Bishopscote Road, Maidenhall Road, Crawley Green Road, Cornell Close and Shaftesbury Road.
A police spokesman said: "This morning's operation did not involved armed officers."