The United States says it will buy heavy water from Iran's nuclear program and expects it to be delivered within a few weeks.
The U.S. Department of Energy said on April 22 that it will buy 32 metric tons of heavy water -- used to make nuclear weapons and nuclear energy -- from Iran for some $8.6 million.
Iran is compelled under last year's landmark nuclear deal between Tehran and six world powers to reduce its stock of heavy water by either selling it or by diluting or disposing of it.
Iran's top nuclear negotiator, Abbas Araqchi, who discussed the sale with U.S. officials in Vienna on April 22, told reporters that the 32 tons have been sold to an American company.
He said Iran has an estimated 70 metric tons of extra heavy water and may sell more.
The deal was criticized by U.S. Speaker of the House Paul Ryan (Republican-Wisconsin), who said in a statement the money paid to Tehran would "directly subsidize Iran's nuclear program."
U.S. Secretary of State John Kerry is due to meet with Iranian Foreign Minister Javad Zarif in New York on April 22.