The White House has sought Iranian government's help in securing the return of Robert Levinson, a retired FBI agent, who has been missing in the Islamic Republic since 2007.
"As we approach the upcoming holiday season, we reiterate the commitment of the US government to locate Levinson and bring him home safely to his family, friends and loved ones," reported Xinhua citing White House spokesperson Jay Carney Tuesday.
The official described Levinson as "one of the longest held Americans in history," as he has never been heard of again since March 9, 2007 when he travelled to Iran's Kish Island on a business trip.
"We welcome the assistance of our international partners in this investigation, and we respectfully ask the government of the Islamic Republic of Iran to assist us in securing Levinson's health, welfare and safe return," Carney said.
Josh Earnest, another White House spokesperson, told reporters that recent negotiations with Iran were related only to its nuclear programme. But President Barack Obama had asked for Iran's help in locating Levinson when he conversed over the phone with his Iranian counterpart Hassan Rouhani in September.
Earnest said there was no progress in locating Levinson, for whose information the FBI offered a $1 million reward last year.