"As we approach the upcoming holiday season, we reiterate the commitment of the United States government to locate Mr. Levinson and bring him home safely to his family, friends and loved ones," the White House said in a statement. "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 Mr. Levinson's health, welfare and safe return."
Levinson, 65, who suffers from diabetes, disappeared on Iran's Kish island while traveling as a private businessman.
In March, Levinson's wife, Christine Levinson, told ABC News she would hold Iran to its promise of helping locate her husband.
During her interview, she said she learned her husband was alive more than a year ago when a hostage video of him was posted on the Internet.