Latest step means Fordow facility will move from its permitted status as a research plant to an active nuclear site.

Iran stepped up activity at its underground Fordow nuclear plant early on Thursday – a move France said showed for the first time that Tehran explicitly planned to quit a historic deal with world powers that curbed its disputed nuclear work.

“With the presence of inspectors from the International Atomic Energy Agency (IAEA), Iran started injecting [uranium] gas into centrifuges in Fordow,” state television reported.

The Atomic Energy Organization of Iran also confirmed the operation, which it said started at 00:00 local time on Thursday (20;30 GMT on Wednesday) following the transfer of 2,800kg (6,172lbs) cylinder containing 2,000kg (4,409lbs) of uranium hexafluoride from Natanz nuclear facility to Fordow.

Earlier, Iran announced 1,044 centrifuges were installed at Fordow.

The United States,which withdrew from the nuclear deal in May 2018 and reimposed sanctions on Tehran, reiterated its criticism, calling Iran’s move a “big step in the wrong direction”.

Iran’s plans to increase its nuclear activity at Fordow raise concerns that Iran is positioning itself for a rapid nuclear breakout. It is now time for all nations to reject its nuclear extortion and increase pressure. — Secretary Pompeo (@SecPompeo) November 7, 2019

Iran insists the latest move is not a violation of the nuclear deal, but is based on the Articles 26 and 36 of the agreement.

In another development that could also aggravate tensions between Iran and the West, diplomats said on Wednesday Iran briefly held an inspector for the UN nuclear watchdog and seized her travel documents, with some describing this as harassment.

Iran said the inspector was prevented from entering the Natanz facility because of a concern she might be carrying “suspicious material”, the semi-official Fars news agency reported.

It said screening equipment at Natanz flashed a warning sign when the inspector passed through so her equipment was searched, she was denied entry, and the IAEA was subsequently informed.

The incident involving an IAEA inspector appeared to be the first of its kind since Tehran’s landmark deal with major powers was struck in 2015, imposing restraints on its uranium enrichment programme in return for the lifting of international sanctions.

Nothing in return

Iran’s decision to inject uranium gas into centrifuges at Fordow, a move that further distances Iran from the accord, was described by Russia as extremely alarming. Iran once hid Fordow from the IAEA until its exposure by Western spies in 2009.

Russian Foreign Minister Sergey Lavrov expressed concern about Tehran’s announcements but said European powers should do their part.

“They are demanding that Iran fulfil all [obligations] without exception, but are not giving anything in return,” he told reporters in Moscow.

The Kremlin has previously called sanctions against Iran “unprecedented and illegal”.

The new nuclear activity was the fourth step announced by Iran since it began responding to Washington’s abandonment of the nuclear deal last year.

French President Emmanuel Macron called Iran’s latest move “grave”, saying it explicitly signalled Iran’s intent for the first time to leave the deal – formally known as the Joint Comprehensive Plan of Action (JCPOA).

“I think that for the first time, Iran has decided in an explicit and blunt manner to leave the JCPOA, which marks a profound shift,” said Macron, who has been at the forefront of efforts by European signatories to salvage the deal after the US withdrew.

1. One of the most frustrating things about where we are now with the JCPOA is that we are once again focusing so much energy on things like centrifuges when the nuclear issue is plainly *not* central to Iran’s contentious status in the global order. — Esfandyar Batmanghelidj (@yarbatman) November 5, 2019

Enrichment possibilities

Behrouz Kamalvandi, a spokesman for the Atomic Energy Organisation of Iran, told state television the agency has delivered 2,000kg of uranium or UF6 to the Fordow plant under the supervision of United Nations inspectors, on Wednesday.

“The restarting of the centrifuges will take a few hours and from midnight, the process of injecting uranium gas into them will begin,” he said.

A spokesman for International Atomic Energy Agency (IAEA) said its inspectors at the site “will report back on relevant activities”.

The nuclear accord, signed in 2015 by Iran, the US, Britain, France, Germany, China and Russia, bans nuclear activity at Fordow, a plant located near the city of Qom and capped the level of purity uranium can be enriched at 3.67 percent – suitable for civilian power generation and far below the 90 percent threshold of nuclear weapons-grade.

Before the deal, Iran used Fordow to enrich uranium to 20 percent fissile purity. Officials have said Tehran could again enrich uranium to 20 percent but there is no need for that right now.

With the injection of uranium gas into its centrifuges, Fordow will move from its permitted status of research plant to become an active nuclear site.