( CNN ) -- The Justice Department on Friday invoked the government 's `` state secrets privilege '' to intervene in a private legal dispute between the owner of a Greek shipping company and a U.S. nonprofit that advocates against Iran 's nuclear program . In a court filing in New York , government lawyers asked a judge to dismiss a lawsuit by Victor Restis against the group United Against Nuclear Iran . Restis claims he was defamed in a UANI campaign that alleged his company had ties to the Iranian government companies that are involved in Iran 's nuclear program . The government filing said an unnamed U.S. agency had determined the case risked revealing government secrets . Restis ' lawyers had sought to compel legal discovery -- the turning over of documents and other information -- from the group , its executives , and from Wall Street investor Thomas Kaplan , who Restis ' lawyers claim is a funder of UANI . UANI lawyers had sought to obtain a deposition of Restis to question him about alleged Iran ties . Friday 's government filing provided no detail of how UANI , Restis , or any others involved could have come to possess U.S. national security secrets . It said that `` disclosure of the information at issue reasonably could be expected to cause serious damage to the national security . '' Kaplan 's lawyers have claimed he has no information relevant to the case . UANI has defended its free speech rights to campaign on the Iran issue . Justice Department lawyers had previously attended hearings in the case and signaled the possibility the government may intervene , citing possible `` law enforcement '' secrets . The filing Friday goes beyond that , and by simply asserting `` state secrets , '' the government limits what can be reviewed in the case . Government lawyers also filed a classified court filing that ostensibly provided more information to the judge . Before becoming president , Barack Obama had criticized the Bush administration for using the state secrets privilege and vowed more transparency . The Obama administration has used the privilege in several cases . Attorney General Eric Holder announced rules that he said would limit the government 's use of the privilege , but leaves his discretion in such cases unaltered . Government lawyers noted the unusual nature of intervening in a private dispute . `` While the United States takes this position reluctantly and only after careful consideration , the only appropriate course in light of this privilege assertion is to dismiss this action in its entirety , '' the filing said .
Justice Department has invoked `` state secrets privilege '' in private dispute . Case involves man who says he was defamed by group United Against Nuclear Iran . Government lawyers filed classified document that may provide more info to judge .