Of far greater concern to the international community is Iran's uranium enrichment facilities and its uranium stockpile
The International Atomic Energy Agency has told member states that it has "verified that 11 metric tonnes of nuclear-grade heavy water have arrived at its destination," the source told AFP.
This brings Iran's stock of heavy water back below the 130-tonne level set out in the nuclear accord with world powers that came into force in January, the watchdog told its members.
Heavy water is not itself radioactive, but is used in certain types of reactor. Plutonium for use in nuclear weapons can be extracted from the spent fuel of such reactors.
In its latest update last month on Iran's compliance with the accord, the IAEA said that Iran's heavy water stock had crept above the 130-tonne mark by 100 kilos.
Iran then said on November 22 that it would ship 11 tonnes to Oman. It also disputes that the 130-tonne level is an upper limit in the 2015 agreement.
Of far greater concern to the international community is Iran's uranium enrichment facilities and its uranium stockpile, which were drastically reduced under the deal.
The IAEA report last month confirmed that Tehran remains in compliance in this area.