The White House said Wednesday Iran is committed to helping U.S. authorities find missing FBI agent Robert Levinson, who disappeared in Iran in 2007.
Spokesman Josh Earnest said the U.S. takes Iran's promise "quite seriously" and is holding the Iranians to it.
"The reason their cooperation is important is the last time that Mr. Levinson was seen, he was in Iran. And so we've got some pretty pointed questions that we are asking the Iranians about what they may know about his current whereabouts," he said.
Earnest said he does not have a lot of information about the discussions with the Iranians. But the FBI said earlier it is encouraged by the cooperation from Tehran.
Secretary of State John Kerry also said Wednesday the Obama administration "will never forget Bob and we will not rest until the Levinson family is whole again."
The United States has offered a $5 million reward for information leading to Levinson's return, but details of his disappearance and detention since 2007 remain a mystery. Iran originally said he was detained by its security services, but authorities in Tehran later said they could not trace what happened to him.
Levinson, whose 68th birthday is Thursday, appeared to be in captivity in photographs his family received five years ago, but otherwise almost nothing is known publicly about his circumstances, or even whether he is still alive. Attention re-focused on the Levinson case earlier this year when Iran released a group of detained Americans including Jason Rezaian, a reporter for The Washington Post.
Levinson's son, Daniel, told VOA's Persian Service the family believes people in the Iranian government know where he is.