China's second new nuclear missile base 'most significant expansion ever' of Beijing's arsenal

The sites were found deep in the Gobi desert. Photo / Planet Labs

China is building a second new nuclear missile base capable of holding dozens of intercontinental ballistic missiles, satellite images appear to show.

The vast site, spread over 770sq km in the Xinjiang region, is thought to house 110 silos for launching weapons, in what has been described as "the most significant expansion of the Chinese nuclear arsenal ever".

Researchers from the Federation of American Scientists used civilian satellite images to examine the Gobi desert near Hami, where Uyghur muslims are believed to be housed in "re-education camps".

They spotted a series of large inflatable domes - typically used by construction teams on military bases to hide the work they are doing below.

The discovery comes just weeks after another silo field was spotted in Yumen, north-east China. According to the James Martin Centre for Nonproliferation Studies, who found the site, there are 120 missile silos there.

China says it has only a "minimum deterrent" of nuclear weapons, which experts estimate to number around 300.

By contrast, the US and Russia have strategic arsenals five times as big and stockpiles of around 5000 weapons each.

But earlier this year, Admiral Charles Richard, who commands the US nuclear forces, said the Chinese nuclear weapons stockpile was "expected to double, if not triple or quadruple, over the next decade".

The site in Yumen. Photo / Planet, Centre for Nonproliferation Studies

"The silo construction at Yumen and Hami constitutes the most significant expansion of the Chinese nuclear arsenal ever," Matt Korda and Hans M Kristensen wrote in a study of the new silo field.

But other experts warned that the rapid expansion might just be a deterrent.

"Just because you build the silos doesn't mean you have to fill them all with missiles," said Vipin Narang, a Massachusetts Institute of Technology professor who specialises in nuclear strategy.

"They can move them around."

Narang told the New York Times the two new silo fields gave the Chinese government "many options".

Chinese President Xi Jinping. Photo / AP

"It's not insane. They make the United States target a lot of silos that may be empty. They can fill these silos slowly if they need to build up their force. And they get leverage in arms control.

"I'm surprised they didn't do this a decade ago," he said.

Earlier this month, Xi Jinping, China's leader, threatened to "bash the heads" of any foreign powers that try to bully Beijing.

"We will never allow any foreign power to bully, oppress or subjugate us," Xi declared in a speech to celebrate the ruling Communist Party's centenary.