CHINA is secretly constructing a massive new military fortress ten times bigger than the Pentagon.

The “Beijing Military City” is kitted with a doomsday bunker ready for WW3 and could serve as a wartime command centre, according to US intelligence.

The Pentagon is famously the world’s largest office building – but will be dwarfed by the new facility which is more than 4km across.

It occupies a sprawling site about 20 miles southwest of the capital Beijing.

There is no noticeable military presence around the complex, yet US intelligence officials suspect it is intended to play a crucial role in China’s future military operations.

Xi Jinping is rapidly building up a nuclear arsenal which, in a decade’s time, could rival that of the US.

With nuclear armament comes the need for more robust protection against nukes from other nations – hence the bunker beneath the fortress.

The construction of the complex was first reported by the Financial Times, with satellite pictures showing its development.

In February 2022, the site was filled with residential buildings and large areas of open land in an area north of the Chonqing Reservoir.

About a year later, the area seemed mostly cleared, setting the stage for a large-scale construction project, which seemed to commence in mid-2024.

By the June of that year, the site had been completely overhauled wit a new system of surrounding tunnels and roads.

According to the Chinese government, the new facility does not exist.

There is no official mention of the construction project, and the Chinese embassy claims no knowledge of it.

But the watertight restrictions around the site suggests otherwise.

Access is strictly prohibited, and all drones and cameras are banned.

Hiking trails near to the site have also been erased to avoid any prying eyes.

A former senior US intelligence official informed the FT that the new command centre might take the place of China’s current military headquarters from the Cold War era.

The source said: “The size, scale, and partially buried characteristics of the new facility suggest it will replace the Western Hills complex as the primary wartime command facility.”

Renny Babiarz, a former imagery analyst at the National Geospatial-Intelligence Agency, told the paper that satellite images appeared to show about 100 cranes working away at the site.

With deep underground tunnels and spaces reinforced in concrete, a China researcher told the FT that the complex had “all the hallmarks of a sensitive military facility”.

They said: “Nearly 10 times bigger than the Pentagon, it’s fitting for Xi Jinping’s ambitions to surpass the US.

“This fortress only serves one purpose, which is to act as a doomsday bunker for China’s increasingly sophisticated and capable military.”

The new base suggests that China has growing military ambitions, and aligns with the Chinese People’s Liberation Army’s goal to reform the military by 2027.