BERLIN (JTA) – A Hamburg court sentenced four men for smuggling products for use in Iran’s nuclear program, believed to be the largest violation so far of the trade embargo with Iran.

Critics said the sentences, ranging from four years in prison to 18 months probation, are too lenient, and called for repercussions at the German Office for Export Control.

According to the Hamburg Abendblatt newspaper, the four sentenced men procured reactor parts for Iran’s heavy water reactor in Arak, but claimed they were sending the goods to Turkey and Azerbaijan.

U.S. intelligence services reportedly had informed German export authorities about the planned illegal shipments in 2009, but the shipments went ahead in 2010 and 2011.

German Member of Parliament Klaus Barthel, economic policy speaker for the opposition Social Democratic Party faction, in recent weeks blasted the Federal Government for refusing to answer questions about the lapse.

This week, the German non-governmental organization Stop the Bomb criticized the lenient sentences and called on Germany to fire the director of the Federal Office for Export Control, Arnold Wallraff.

Despite all warnings, “they still gave their permission for the exports,” Stop the Bomb Executive Director Michael Spaney told JTA. ”It is a major scandal.”

Despite the reported U.S. warnings, a German businessman identified as Rudolf M. was able to deliver 92 valves for nuclear power plants via an Iranian middleman, Hossein Tanideh, who currently is in jail in Turkey. Rudolf M. was assisted by three German-Iranians identified as Gholamali K.,  Kianzad K. and Hamid K.

Gholamali K. also helped organize delivery of nearly 900 valves from India.

The Hamburg judge said the four men had not only violated the embargo but endangered German foreign relations. “They knew exactly that this was business with a nuclear background,” he said.