Seven men have been arrested on suspicion of terror offences after firearms and other weapons were found "hidden" in a car, police said today.
West Midlands Police said one man from West Yorkshire and six from the West Midlands are being questioned, following a series of arrests this week.
A spokesman said: "The arrests followed a routine stop of a vehicle by police on the M1 motorway in South Yorkshire on Saturday (June 30).
"The car was impounded on suspicion of having no insurance.
"Firearms, offensive weapons and other material were later found hidden inside, prompting police to take action to trace and arrest the driver, passenger and others suspected of being involved."
Police said three men aged 23, 26 and 27 from Sparkhill, Birmingham, were arrested on Tuesday morning.
Three more suspects, a 22-year-old from Alum Rock, Birmingham, a 24-year-old from the Moseley area of the city, and a 22-year-old from Smethwick, West Midlands, were arrested on Wednesday evening.
A 43-year old man from Kirklees, West Yorkshire, was detained on Thursday.
Detective Chief Superintendent Kenny Bell, head of the West Midlands Counter Terrorism Unit, said: "As soon as the items were discovered in the impounded vehicle, our priority was to protect the public by pursuing and arresting those we believed to be involved."
Police said the contents of the car were undergoing forensic analysis and the suspects' homes had been searched.
Detectives have been given extra time to question the three men arrested on Tuesday, after the initial 48-hour detention period ran out. They now have until next Tuesday morning to charge or release the men, or apply for a further warrant.
All seven men are being held in the West Midlands.
A police spokesman said the 43-year-old man was arrested in Ravensthorpe, Dewsbury.
West Midlands Police said the car was stopped between junctions 33 and 34 of the southbound M1.
Two guns were found, they were not loaded and were not automatic weapons, the force said.
A small amount of ammunition was also found.