A man has been arrested under the Terrorism Act, police said.
The 30-year-old, from the Sparkhill area of Birmingham, was taken into custody early this morning, on suspicion of possessing material likely to be of use to a terrorist and of distributing terrorist publications.
Detective Superintendent Kenny Bell, head of investigations at the West Midlands Counter Terrorism Unit, said: "This arrest comes as a result of a long, detailed and ongoing inquiry.
"The operation was carried out by unarmed officers in a way intended to cause the minimum amount of disruption for those in the immediate vicinity."
Police said the man's home address and a residential property in the Kings Heath area of the city were being searched.
Officers seized computer equipment from the Sparkhill property.