A new law passed by the U.S. Congress calls on the Pentagon to come up with a plan to neutralize nuclear weapons stored in Chinese subterranean storage facilities.

The existence of the so-called "Underground Great Wall," which sits hundreds of meters deep inside a mountainous area and stretches for 5,000 km, was first revealed in 2009.

Citing Defense News, China's state-run Global Times reported on Monday that the 2013 National Defense Authorization Act signed by U.S. President Barack Obama on Jan. 2 "orders the commander of the U.S. Strategic Command to submit a report by Aug. 15 on the 'underground tunnel network used by People's Republic of China with respect to the capability of the United States to use conventional and nuclear forces to neutralize such tunnels and what is stored within such tunnels.'"

A team of researchers at Georgetown University announced in November last year that the "Underground Great Wall" in western Sichuan Province can store 3,600 nuclear warheads. But the Global Times said the claim is exaggerated and accused the U.S. of using Cold War propaganda tactics.