It was not a routine traffic stop.
At a toll road booth in northern Spain on Friday, Spanish police swooped in to inspect a trailer truck and seized what they said was material destined for Iran's nuclear program, an Interior Ministry statement said.
Two people were arrested.
The trailer truck contained 44 valves made of a nickel and chromium alloy that, due to their "high resistance to corrosion, make them particularly apt for use in the nuclear industry," the ministry said.
Police also seized mounting accessories, export documents to Iran, bank statements and computer information, it said.
The traffic stop at the toll booth resulted, the ministry said, from an investigation that began in Spain last March aiming to restrict the flow of materials and technology of so-called "dual use" items, which can be used for nuclear weapons programs.
The ministry said police also searched a business, linked to the trailer truck, in an industrial park in the northern Spanish province of Alava. They brought along one of the suspects, whom police described as the company's sales chief covering various countries, including Iran.
The European Union and the United States have sanctions in place against Iran's nuclear program.