Iran builds at underground nuclear facility amid US tensions

Iran has begun construction on a site at its underground nuclear facility at Fordo amid tensions with U.S. over its atomic program, satellite photos obtained Friday by Associated Press show. Iran has t publicly ackwledged any new construction at Fordo, whose discovery by West in 2009 came in an earlier round of brinkmanship before world powers struck 2015 nuclear deal with Tehran.

While purpose of building remains unclear, any work at Fordo likely will trigger new concern in waning days of Trump administration before inauguration of President-elect Joe Biden. Already, Iran is building at its Natanz nuclear facility after a mysterious explosion in July re that Tehran described as a sabot attack .

“Any changes at this site will be carefully watched as a sign of where Iran’s nuclear program is headed," said Jeffrey Lewis, an expert at James Martin Center for nproliferation Studies at Middlebury Institute of International Studies who studies Iran.

Iran's mission to United Nations did t immediately respond to a request for comment. International Atomic Energy ncy, whose inspectors are in Iran as part of nuclear deal, also did t immediately respond to a request for comment. Construction on Fordo site began in late September. Satellite ims obtained from Maxar Techlogies by AP show construction taking place at a rthwest corner of site, near holy Shiite city of Qom some 90 kilometers (55 miles) southwest of Tehran.

A Dec. 11 satellite photo shows what appears to be a dug foundation for a building with dozens of pillars. Such pillars can be used in construction to support buildings in earthquake zones. construction site sits rthwest of Fordo's underground facility, built deep inside a mountain to protect it from potential airstrikes. site is near or support and research-and-development buildings at Fordo.

Among those buildings is Iran's National Vacuum Techlogy Center. Vacuum techlogy is a crucial component of Iran's uranium-gas centrifuges, which enrich uranium. A Twitter account called Observer IL earlier this week published an im of Fordo showing construction, citing it as coming from South Korea's Korea Aero Research Institute.

AP later reached Twitter user, who identified himself as a retired Israeli Defense Forces soldier with a civil engineering background. He asked that his name t be published over previous threats he received online. Korea Aero Research Institute ackwledged taking satellite photo.

Trump in 2018 unilaterally withdrew U.S. from Iran's nuclear deal, in which Tehran had agreed to limit its uranium enrichment in exchange for lifting of ecomic sanctions. Trump cited Iran's ballistic missile program, its regional policies and or issues in withdrawing from accord, though deal focused entirely on Tehran's atomic program.

When U.S. ramped up sanctions, Iran gradually and publicly abandoned deal's limits as a series of escalating incidents pushed two countries to brink of war at beginning of year . Tensions still remain high. Under 2015 nuclear deal, Iran agreed to stop enriching uranium at Fordo and instead make it “a nuclear, physics and techlogy center.”

“This location was a major sticking point in negotiations leading to Iran nuclear deal,” Lewis said. “ U.S. insisted Iran close it while Iran’s supreme leader said keeping it was a red line.”

Since deal's collapse, Iran has resumed enrichment re . Shielded by mountains, facility also is ringed by anti-aircraft guns and or fortifications. It is about size of a football field, large eugh to house 3,000 centrifuges, but small and hardened eugh to lead U.S. officials to suspect it had a military purpose when y exposed site publicly in 2009.

As of w, Iran is enriching uranium up to 4.5%, in violation of accord’s limit of 3.67%. Iran's parliament has passed a bill that requires Tehran to enrich up to 20% , a short technical step away from weapons-grade levels of 90%. bill also would throw out IAEA inspectors.

Experts say Iran w has eugh low-enriched uranium stockpiled for at least two nuclear weapons, if it chose to pursue m. Iran long has maintained its nuclear program is peaceful. While Iranian President Hassan Rouhani opposed bill, country's Guardian Council later tweaked and approved it. bill seeks to pressure European nations to provide relief from crippling U.S. sanctions.

Meanwhile, an Iranian scientist who created its military nuclear program two decades ago recently was killed in a shooting outside of Tehran . Iran has blamed Israel, which has long been suspected of killing Iranian nuclear scientists over last decade, for attack. Israel has t comment. 

(Im Credits: AP)