BEIJING — U.S. Defense Secretary Robert Gates is getting a rare glimpse of China's nuclear weapons headquarters today.

"I'm looking forward to it. I think it'll be interesting," Gates said.

The weapons command center in the Beijing suburb of Qinqhe is a site a few U.S. officials have visited previously, including former U.S. Defense Secretary Donald H. Rumsfeld in 2005, so Gates is unlikely to learn much about China's capabilities that was not already known. Chinese military officials also routinely scrub all traces of truly sensitive materials before allowing Westerners inside such places, as Gates seemed to acknowledge Tuesday.

"I'm not quite sure what I'll see," Gates said with a slight smile.

Still the visit to the base was sought by the United States to balance the 2009 visit of a senior Chinese general to the American equivalent facility, U.S. Strategic Command headquarters in Nebraska.

"I hope I have an equal opportunity," Gates said to reporters traveling with him, but who were barred from the site.

The Chinese base maintains control over nuclear and conventional strategic missile forces, although U.S. analysts have said wartime operations probably would be conducted from another, more secretive site. China has short-, medium-, long-, and intercontinental-range ballistic missiles.

China maintains a nuclear arsenal of about 200 warheads deliverable by land- and submarine-based missiles as well as bomber aircraft, according to the Federation of American Scientists.