Levinson went missing on March 9, 2007, during a visit to the Iranian resort island of Kish. His wife, Christine, told the Miami Herald he was there investigating cigarette smuggling for his private security firm.
The FBI in a statement stressed that it was the lead agency in the investigation, adding it was continuing to seek information regarding his whereabouts.
"Although the FBI has not received any information from Iranian authorities to date about Mr. Levinson, we are willing to cooperate fully with Iranian investigators in our effort to find Mr. Levinson and bring him home safely," the statement continued.
The U.S. State Department weighed in on the matter on the occasion of the 1,000th day since his disappearance, calling on Tehran to make sure Levinson is returned to the United States safely.
Christine Levinson traveled to Iran in December 2007 to seek information on the disappearance. She told the Herald she continued to pay her husband's cell phone bill in hopes that he would use it to phone home.