A 43-year-old man from Kirklees, West Yorkshire has been arrested along with six others from the West Midlands as part of a terror investigation.
They have all been detained on suspicion of the commission, preparation or instigation of acts of terrorism (Terrorism Act 2000).
The arrests followed a routine stop of a car by the police on the M1 in South Yorkshire on June 30. The cars were impounded on suspicion of having no insurance. Firearms, offensive weapons and other material were later found inside. Those items are now being forensically tested.
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.
Our enquiries are ongoing.
More top news
Polls suggest immigration is the biggest issue for voters in Yorkshire and Lincolnshire ahead of the General Election in May.
Afternoon weather with Jon Mitchell
More than 100 Auschwitz survivors from at least 17 countries were expected to attend the main ceremony at the concentration camp.