The United States is buying Iran's heavy water for its nuclear reactors through an intermediary despite sanctions, the country's top diplomat said on Saturday.
Speaking at an event in the Iranian capital Tehran, Iran's Foreign Minister Hossein Amir-Abdollahian echoed what the officials of Iran's nuclear agency have repeatedly said.
He said Iran's most sanctioned sectors -- missile and nuclear -- are also the most advanced, noting that the US has been purchasing Iran's heavy water through an intermediary.
Amir-Abdollahian said a European official once told him that after testing they found Iran's heavy water of the "highest quality" in the world.
Heavy water, a form of water that contains heavy hydrogen, is described as the second most sought-after nuclear material after uranium, and Iran is one of the few countries that produces it with high purity.
In September, spokesperson and deputy chief of Iran's nuclear agency, Behrouz Kamalvandi, said the heavy water produced in Iran "ranks first in the world in terms of quality," adding that European countries have expressed interest in it.
He said Iran sells 1 liter of heavy water for $1,000, which is instrumental in the diagnosis and treatment of critical ailments like cancer.
In August, Iran's nuclear agency chief Mohammad Eslami said the heavy water of the Khandab nuclear facility in central Iran has particularly high demand, adding that heavy investments are being made in heavy water derivatives.
The purchase of Iran's heavy water was previously revealed by Kamalvandi in April when he said Washington "once again" showed interest in purchasing heavy water from Iran for its "high quality."
"We should know that the heavy water produced in Iran is among the best in the world and even the Americans were once trying to purchase it after they analyzed its properties," he was quoted as saying at the time.
The stalemate in protracted talks to revive the 2015 nuclear pact, which allowed Iran to keep up to 130 tons of heavy water, has escalated tensions between Tehran and Washington.
In April 2016, after the landmark agreement was clinched, US officials were quoted as saying that they intended to buy 32 metric tons of heavy water from Iran worth $8.6 million, a move Republicans criticized.
It was soon followed by legislation in the US House of Representatives that blocked the purchase of heavy water from Iran.
In November 2019, the UN nuclear watchdog claimed that Iran's stock of heavy water for reactors had crossed the limit set under its 2015 agreement with world powers, reaching 131.5 tons.
Arak heavy water nuclear reactor, also known as Arak or IR-40, located in northeast Iran, is the main facility in Iran for the production of heavy water derivatives.