A second man has been arrested under the Terrorism Act after potentially explosive materials were seized at a house in Goole in East Yorkshire.
The 31-year-old from Goole, was arrested in the Dundee area of Tayside at 0130 GMT on Saturday.
Another 31-year-old was arrested in Goole on Wednesday following a search of a house in Pasture Road.
The man arrested in Dundee will be brought to Leeds for questioning by Counter Terrorism Unit (CTU) officers.
On Friday, a court approved a warrant to hold the man detained on Wednesday for seven days.
He was being held pending further inquiries by CTU officers and the results of forensic tests, police said.