Four men have been arrested in Germany on suspicion of illegally supplying Iran with parts needed to build a nuclear reactor.
The suspects were held following searches of homes and business in Hamburg, Oldenburg and Weimar.
They are accused of using front companies in Turkey and Azerbaijan to supply the parts in deals worth millions of euros.
Germany has an embargo on nuclear-related trade with Iran.
Many Western countries have concerns about Iran’s nuclear programme, but Iran insists it is for peaceful purposes.
Tehran is currently building a heavy-water reactor near the central town of Arak.