International Atomic Energy Agency (IAEA) Director General Yukiya Amano said [press release] Thursday that Iran has repeatedly failed to keep its stockpile of heavy water below 130 metric tons. Heavy water can be used for nuclear energy [Britannica backgrounder] or for the development of nuclear weapons. The 130 metric ton requirement was imposed on Iran by a 2015 nuclear agreement (JCPOA) [text] between Iran, the US, the UK, China, France, Russia and Germany. Amano said that Iran had followed the other parts of the agreement, but:

For the second time since implementation of the JCPOA began, Iran’s inventory of heavy water exceeded 130 metric [tons]. Iran has since made preparations to transfer a quantity of heavy water out of the country, under the verification and monitoring of the Agency. Once it has been transferred, Iran’s stock of heavy water will be below 130 metric [tons]. It is important that such situations should be avoided in future in order to maintain international confidence.

US President-Elect Donald Trump had pledged during his campaign to undo the Iran nuclear deal but has not publicly commented on the matter since last week’s election.

The US House on Wednesday approved [JURIST report] extending sanctions against Iran. The IAEA reported [text, PDF] as recently as September that Iran had successfully maintained a stockpile of “heavy water” below the threshold. The Iran nuclear agreement was reached [JURIST report] in July 2015 after 20 months of negotiations. Iran has repeatedly claimed [JURIST report] that it has a right to nuclear technology, and that its aims are peaceful.