Iran is holding talks with Russia to sell it about 40 tonnes of heavy water from its nuclear program, Iran's deputy foreign minister Abbas Araqchi was quoted as saying by an Iranian news agency.
Araqchi, who is also a top nuclear negotiator, said late on Sunday that the United States had been the first buyer of Iranian heavy water and some other world powers, including Russia, were now showing an interest.
"We are negotiating with Russia to sell 40 tonnes of heavy water," he said.
The heavy water is not a radioactive substance and the nuclear deal gives Iran the right to sell, dilute or dispose of it under certain conditions.
In conformity with last year's landmark nuclear deal between Iran and world powers, Tehran is responsible for diminishing its stock of heavy water which is a component of making nuclear weapons and producing nuclear energy.
Russia also announced buying 40 tonnes of heavy water from Iran, Russian foreign ministry said on Monday.
The deal was reached between Iran and six world powers including Britain, China, France, Germany, Russia and the United States aimed at monitoring Iran's nuclear work for over 12 years in exchange for immediate relief for the country from economic sanctions that have long crippled its economy.
US Secretary of State John Kerry met with Iranian Foreign Minister Mohammad Javad Zarif on April 23, for the second time in a week, announcing Washington agreed to buy 32 tonnes of Iranian heavy water.
In January, Iran dismantled the core of its Arak heavy water nuclear reactor and filled it with cement as required under a nuclear deal. The United States, Russia and China have agreed to participate in the redesign and the construction of a modernised reactor.