Foreign Minister Hossein Amirabdollahian says Iran and the United States have reached an agreement to exchange prisoners, but Washington denied it as false.
A White House official said the United States was committed to securing the release of Americans held in Iran.
For years, Tehran has sought the release of more than a dozen Iranians in the United States.
The Islamic Republic, which is holding dozens of Iranian dual nationals and foreigners, has been accused by rights activists of arresting them to try to extract concessions from other countries. Iran has dismissed the charge.
