Federal prosecutors say they have charged three German-Iranian dual nationals and a German man with breaking export laws for allegedly supplying Iran with parts needed to build a nuclear reactor in violation of the country's trade embargo.

Prosecutors said in a statement Monday suspect Hamid Kh., 80, set up contact for Gholamali Ka., 70, and his son Kianzad Ka., 25, with German businessman Rudolf M., 78, whose Thuringia firm produced valves needed for a nuclear reactor's construction. Their last names were not released in accordance with German privacy laws.

The group is accused of supplying Iran with 92 German-made valves, and another 856 Indian-made valves, in 2010 and 2011.

They're accused of supplying the parts through front companies in other countries in deals worth millions of euros in total.