Red China's massive military buildup

Satellite pictures... by DAVID GARDNER

Photographs emerged last night that appeared to confirm fears in Washington that China is building a giant underground nuclear submarine base on a tropical island.
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The pictures, obtained by respected military magazine Jane's Intelligence Review, have raised concerns that the Chinese have carved out a secret base straight out of the plot of a James Bond thriller.

They show vast tunnel entrances that are thought to lead to huge caverns capable of hiding up to 20 nuclear submarines from spy satellites.

Sanya is a fast-developing holiday resort that has hosted the Miss World competition since 2003. It is on Hainan Island, which is about 160 miles from the coast of Vietnam.

Jane's Intelligence Review says the base has implications "for China's control of the South China Sea and the strategically vital straits in the area, and underlines Beijing's desire to assert tighter control over this region".
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The secrecy around the build-up is likely to lead the U.S. to put more pressure on the Chinese to come clean with its plans and raises further questions about Beijing's relationship with the rest of the world in the run-up to the summer Olympics.

If it's all about "defense" then why the secrecy?