A view of the Arak heavy-water project
A view of the Arak heavy-water projectReuters

The U.S. State Department said on Wednesday that Iran is taking steps to ship out heavy water produced in excess of a soft limit set under its nuclear deal with major powers, Reuters reported.

The comments came after the UN atomic watchdog, the International Atomic Energy Agency (IAEA), revealed that Iran had surpassed the threshold of heavy water it is permitted to produce under the agreement.

"It's important to note that Iran made no effort to hide this," State Department spokesman Mark Toner told a regular press briefing when asked about the report, according to Reuters.

This marks the second time Tehran has surpassed the 130 metric ton threshold for heavy water, a material used as a moderator in reactors like Iran's unfinished one at Arak, since the deal was put in place in January.

Last February, the IAEA said Iran had briefly exceeded the limit and that its stock of heavy water had reached 130.9 metric tons. Shortly thereafter, 20 tons of heavy water were shipped out of the country.

On Tuesday, Iran had 130.1 tons of the material, the IAEA said in a confidential report seen by Reuters.

In September, the IAEA indicated that Iran had kept to the nuclear deal to which it agreed with six world powers, which limits its stockpiles of substances that could be used to make atomic weapons.

The report came after a U.S. think-tank said Iran had been secretly allowed to overstep certain thresholds in order to get the deal through on time.

The White House later dismissed the idea that Iran was secretly allowed to skirt restrictions on its uranium stockpile, with White House spokesman Josh Earnest insisting Iran “has been in compliance with the agreement” since January 16, when the deal was implemented.