China may be using thousands of miles of underground tunnels to hide a nuclear missile arsenal that is far bigger than current estimates, according to researchers.
They spent three years translating secret military documents, scouring the internet and studying satellite images for clues - and concluded that China may have as many as 3,000 missiles, compared with general estimates of between 80 and 400.
The researchers at Georgetown University, led by a former senior Pentagon official, concentrated on a 3,000-mile network of tunnels dug largely in Sichuan province by the Chinese Second Artillery, a secretive unit responsible for protecting the country's nuclear weapons.
|Stockpiling: Missiles being test-fired at an undisclosed location. A group of university students have uncovered evidence that China may have many more nuclear weapons than previously thought
In 2008, thousands of radiation technicians were sent to the region after it was hit by a huge earthquake. When TV pictures showed oddly collapsed hills across the province, officials eventually admitted there was a network of tunnels underneath, dubbing it their 'Underground Great Wall'.
The 363-page study, as yet unpublished, has been discussed in Congress and circulated among defence officials. It was commissioned as 'homework' by the students' professor, Phillip Karber, a prominent Washington defence strategist during the Cold War.
'It's not quite a bombshell, but those thoughts and estimates are being checked against what people think they know based on classified information,' said a defence department official.
Critics have questioned the study's use of internet research, including blogs and even a Chinese TV drama about artillerymen.
Nuclear analyst Gregory Kulacki said the tunnels might encourage the Chinese to have fewer rather than more missiles in the belief that they were better protected.
Nuclear non-proliferation campaigners have also attacked the report, saying it will undermine efforts to reduce atomic weapon stockpiles. But Mark Stokes of the Project 2049 Institute, an international security think-tank, said the report highlighted 'the uncertainty about what China has'.
Professor Karber said: 'I don't have the slightest idea how many nuclear weapons China really has, but neither does anyone else in the arms-control community.
'That's the problem with China - no one really knows except them.'
China has long been the most secretive of the five nuclear powers recognised by the international Non-Proliferation Treaty.
While Russia and America have bilateral treaties that ensure their stockpiles are monitored, the Chinese have simply claimed they keep a small number of missiles for 'minimum deterrence'.The U.S. has 5,000 nuclear warheads, and Russia 8,000.
© Daily Mail, London