Iran has been significantly expanding its covert nuclear weapons development since 2009, it has emerged. New intelligence uncovered by Iranian opposition group NCRI reveals that the regime's Organisation of Defensive Innovation and Research (SPND) is running a secret programme to boost nuclear warhead capability, including mounting them on ballistic missiles able to strike targets over 1,900 miles away. The revelations come as Tehran prepares for a fourth round of proposed nuclear talks with the US in Muscat next week, with experts predicting they may derail negotiations.

At the heart of this effort is the Ivanaki (Eyvanekey) facility, a sprawling 2,500-acre site in Semnan Province, northern Iran. Publicly, it is presented as a paint and chemical production site operated by Diba Energy Sina. In reality, it is used for the construction of nuclear weapon components.

Operational since around 2013, Ivanaki is one of several covert facilities established after Iran's previous nuclear weapons programme, the Amad Plan, was exposed and halted in 2003.

Iranian scientists are now believed to be using tritium, a radioactive hydrogen isotope, to increase the yield of implosion-type devices and enable the development of hydrogen bombs.

SPND has recruited nuclear fusion specialists from the Atomic Energy Organisation of Iran, including Dr Ebrahim Haji Ebrahimi and Hadi Zaker Khatir. In 2013, universities were instructed not to publish or host research on fusion or tritium.

The Ivanaki site is heavily guarded. Military roads, checkpoints, and surveillance restrict access. The IRGC Aerospace Force has deployed a Qadir long-range radar and missile defence unit nearby.

Its strategic location just 55km southeast of Tehran reflects its importance. Ivanaki was overseen in its early years by Iran's top nuclear scientist, Mohsen Fakhrizadeh Mahabadi, who was assassinated in 2020.

The site includes three main sections, with large hangars and underground facilities. The surrounding area is a military zone, off-limits to civilians.

Intelligence sources attached to the People's Mojahedin Organisation of Iran (PMOI/MEK) say Ivanaki is just one part of a wider SPND programme, including four other military-linked sites in Semnan: the Garmsar radar site, the Shahroud missile site, and an expanded Semnan missile site.

Together, they support Iran's ambitions to field long-range missile systems capable of carrying nuclear warheads.

Supreme Leader Ali Khamenei initially rejected overtures by former US President Donald Trump. But the impact of US sanctions, the collapse of Iran's £23 billion investment in Syria, and rising domestic unrest have forced a shift.

Iran now faces renewed sanctions under snapback provisions due in October. Trump withdrew from the 2015 JCPOA nuclear deal in 2018, calling it a "bad deal", though the UK, Germany and France remain committed.

"Iran's goal right now is survival," said Megan Sutcliffe of the Sibylline strategic risk group, as she issued an urgent warning to the Middle Eastern nation.

"The regime faces a choice: continue violating agreements and risk collapse and unrest, or accept temporary limitations for economic relief. With Khamenei's age, succession is likely front of mind."

The regime has not disclosed the SPND sites to US envoy Steve Witkoff.

Instead, it has used front companies under the holding group Pishtazan-e Tose'e San'ati Aria Razi (Petsar), which claims to work in oil and gas. Its founding chairman, IRGC Brigadier General Naser Maleki, was sanctioned by the UN for nuclear and missile activity. Other board members are also tied to Iran's defence sector.

Diba Energy Sina, which operates Ivanaki, is led by chemistry experts Mahmoud Sanayei Zadeh and Javad Mirzaei. Their published work on chemical separation aligns with their reported activities at the site.

If verified, the revelations would represent a major breach of Iran's international obligations and could reshape strategic calculations around its nuclear intentions.

"The evidence is plausible when we compare it to what the regime has been aiming for," said Sutcliffe.

"Long-range missile development, bolstering delivery systems, and guarding patterns all match known behaviour."

She warned that gaps in disclosure could disrupt diplomacy.

"One of the main complaints from Trump's team was the lack of proper disclosure before negotiations. If this site hasn't been declared, it will increase pressure on talks."

Alireza Jafarzadeh, Deputy Director of the US office of the National Council of Resistance of Iran, said: "This latest revelation shows again that the regime's nuclear programme is aimed squarely at building weapons.

"For the past 30 years, every stage of this programme has been exposed by the NCRI and its network, forcing the regime to admit what it denied.

"Nuclear weapons are a pillar of the regime's survival strategy. This has nothing to do with civilian energy.

"Two trillion dollars have been spent on this programme in three decades, while investment in Iran's oil and gas sector has dried up. Much of the fuel used domestically is now imported.

"The regime's policy is to drag and delay negotiations while sprinting toward nuclear weapons. Now is the time to break that cycle."