US Secretary of State John Kerry has described yesterday's shipment of more than 11 tonnes (25,000 pounds) of low-enriched uranium materials from Iran to Russia as "one of the most significant steps" the Middle Eastern country has taken toward fulfilling its commitments under the nuclear accord it signed with world powers earlier this year.

October 18 marked Adoption Day of the Joint Comprehensive Plan of Action (JCPOA), the international agreement limiting Iran's nuclear program in return for the lifting of economic sanctions. The JCPOA was signed in July by Iran and the E3/EU+3 (China, France, Germany, Russia, the UK and the USA - also referred to as the P5+1 - plus the European Union). Under its terms, Iran agreed to limit its uranium enrichment activities, eliminate its stockpile of medium-enriched uranium and limit its stockpile of low enriched uranium over the next 15 years. The International Atomic Energy Agency (IAEA) is tasked with overseeing Iran's actions under the agreement.

"Five months after we, the European Union, and our P5+1 partners finalized the Joint Comprehensive Plan of Action with Iran, I remain so proud of our team in achieving what was truly one of our most important accomplishments of 2015 - ensuring that Iran's nuclear program is exclusively peaceful going forward," Kerry said in a written statement published on his official website. "As we get closer to Implementation Day, the next major milestone in the JCPOA, I am pleased to report that we have seen important indications of significant progress towards Iran completing its key nuclear commitments under the deal."

Implementation Day will come when the IAEA verifies that Iran has completed all of these nuclear commitments, which increase Iran's "breakout time", Kerry said, to obtain enough nuclear material for a weapon to one year, up from less than 90 days before the JCPOA.

Yesterday's shipment included the removal of all of Iran's nuclear material enriched to 20% that was not already in the form of fabricated fuel plates for the Tehran Research Reactor. This removal of all this enriched material out of Iran is a significant step, Kerry said, towards Iran meeting its commitment to have no more than 300 kg of low-enriched uranium by Implementation Day. The shipment "more than triples" the previous 2-3 month breakout timeline for Iran to acquire enough weapons grade uranium for one weapon. This is "an important piece of the technical equation", Kerry said, that ensures an eventual breakout time of at least one year by Implementation Day.

The IAEA now must verify that Iran's enriched uranium stockpile is 300 kg or less, as well as confirm that Iran has met all of its other key nuclear steps in the JCPOA before Implementation Day can occur. These steps include, Kerry noted, "removing much of Iran's uranium enrichment infrastructure, which we understand Iran is moving quickly to achieve". Iran must also remove and render inoperable the existing core of the Arak Reactor.

The IAEA is also continuing its own preparations to implement the extensive monitoring and verification regime of Iran's entire nuclear program, as specified in the JCPOA. On December 15, the IAEA's Board of Governors passed a consensus resolution to turn the Vienna-based agency's efforts to full implementation of the JCPOA and the enhanced monitoring and verification tools it provides.

Kerry noted the contribution a number of countries had made to make yesterday's shipment possible. "Russia, as a participant in the JCPOA and a country with significant experience in transporting and securing nuclear material, played an essential role by taking this material out of Iran and providing natural uranium in exchange," he said.

"Kazakhstan contributed significantly to this effort as well, providing some of the natural uranium material that Iran has received in exchange for its enriched material, and helping to facilitate the shipment. Kazakhstan's contribution builds on its hosting of early rounds of the P5+1 talks that led to the successful conclusion of the JCPOA." Azerbaijan also played a key role in facilitating the shipment, he added.

And Norway, "a country long committed to non-proliferation and a country that matches that commitment with actions", contributed critical funding to the commercial transactions involved in reducing the amount of enriched uranium in Iran, Kerry said, and also provided expertise in managing some of these transactions.