Iran begins construction at underground nuclear facility amid US tensions

Tehran, Iran

Iran has begun construction at its underground nuclear facility at Fordo amid tensions with the US over its atomic programme.

According to The Associated Press, Iran has so far not publically acknowledged any new construction at Fordo, whose discovery by the West in 2009 came in an earlier round of brinkmanship before world powers struck the 2015 nuclear deal with Tehran.

Construction on the Fordo site began in late September. Satellite images obtained from Maxar Technologies by the AP show the construction taking place at a northwest corner of the site, near the holy Shiite city of Qom some 90 kilometers (55 miles) southwest of Tehran.

The construction site sits northwest of Fordo's underground facility, built deep inside a mountain to protect it from potential airstrikes. The site is near other support and research-and-development buildings at Fordo.

Trump in 2018 unilaterally withdrew the US from Iran's nuclear deal, in which Tehran had agreed to limit its uranium enrichment in exchange for the lifting of economic sanctions.

Trump cited Iran's ballistic missile programme, its regional policies and other issues in withdrawing from the accord, though the deal focused entirely on Tehran's atomic ambitions.

When the US ramped up sanctions, Iran gradually and publically abandoned the deal's limits as a series of escalating incidents pushed the two countries to the brink of war at the beginning of the year. 

Since the deal's collapse, Iran has resumed enrichment at Fordo.

Tensions still remain high.

The facility is shielded by the mountains, and is ringed by anti-aircraft guns and other fortifications.

Iran is already building at its Natanz nuclear facility after a mysterious explosion in July there that Tehran described as a sabotage attack. The purpose of the building at Fordo, however, remains unclear.