On Tuesday, Iran charged that Saudi Arabia and the United States worked together to abduct scientist Shahram Amiri after he traveled to Saudi Arabia in May for an Islamic pilgrimage.
The United States has denied having any information on the Amiri case.
A Saudi Foreign Ministry spokesman, Osama Nugali, said Wednesday Saudi authorities searched for Amiri at Iran's request but could not find him. The official says the search covered the holy cities of Medina and Mecca.
Iranian parliament speaker Ali Larijani accused the United States Wednesday of acting like a "terrorist" by abducting Amiri. He said both Washington and Riyadh must be held accountable.
A U.S. State Department spokesman said Tuesday Washington is aware of the Iranian accusations but refused further comment.
Iran alleges that Amiri is one of 11 Iranians detained by the United States. Iran's semi-official Mehr news agency published the names of the Iranians Wednesday.
Another name on the list is former Iranian deputy defense minister Ali Reza Asgari, who disappeared in Turkey in 2007. Mehr says Iran has evidence that Asgari was transferred to the United States. Washington has denied involvement in his disappearance.
Some information for this report was provided by AFP and AP.