WASHINGTON (AP) – Defense Secretary Donald H. Rumsfeld is hoping China will reveal more about a massive military that the Bush administration sees as a potential near-term threat to U.S. interests in Asia and a possible global rival in the future.

Rumsfeld departs Monday on his first trip to China as defense secretary, marking a new opening to the country. China’s military, with about 2.5 million people under arms, is the largest in the world, and Rumsfeld wants Beijing to detail more about the scope of its budget and the intentions of its leaders.

China agreed to allow Rumsfeld to visit 2nd Artillery Corps headquarters at Qinghe, which runs its strategic missile forces. Rumsfeld would be the first U.S. official ever to see the complex, according to Pentagon officials speaking on condition of anonymity.

The Chinese, however, denied Rumsfeld’s request to visit the Western Hills command center, a secret underground facility that serves as a national military command post.

No foreigner is believed to have been inside Western Hills, although Chinese officials have visited the Pentagon.

Rumsfeld is scheduled to meet with President Hu Jintao, who also is chairman of the Central Military Commission, which runs the military, and other senior officials, including Rumsfeld’s counterpart, Gen. Cao Gangchuan.

Rumsfeld leaves Washington with few expectations of major breakthroughs in the topsy-turvy relationship with China, according to aides.

But many see his visit as bringing the United States and China full-circle from the most recent low point in relations: the April 2001 collision of a Chinese jet and a U.S. Navy spy plane.

That incident infuriated Rumsfeld, who responded by breaking off U.S. military contacts with China for a time. He has remained publicly skeptical of China’s intentions, saying at an Asia conference last June that by Pentagon calculations China’s defense budget was the third largest in the world, behind the U.S. and Russia.

“Since no nation threatens China, one must wonder: Why this growing investment? Why these continuing large and expanding arms purchases?” Rumsfeld said. He was alluding to China’s expanding missile forces, which pose a threat not only to Taiwan and elsewhere in Asia but potentially even to the U.S.

U.S. officials were taken aback when a Chinese general said last July that Beijing might respond with nuclear weapons if the U.S. were to attack China in a conflict over Taiwan. Maj. Gen. Zhu Chenghu, a dean at China’s National Defense University, said this was his personal view and was not official government policy.

Rumsfeld’s visit, only the third by a U.S. defense secretary in the past decade and the first since 2000, is intended in part as a precursor to a trip that President Bush plans for November.

Rumsfeld’s visit is “long overdue, very welcome, and hopefully will help to restore some trust and momentum to the U.S.-China military and strategic relationship,” said David Shambaugh, director of the China Policy Program at George Washington University. “Yet the depth of distrust and misperceptions in both military establishments toward the other is palpable and not easily overcome.”

Beijing cut off military contacts with Washington in May 1999 after rejecting a U.S. government claim that the bombing of the Chinese Embassy in Belgrade, Yugoslavia, by a B-2 stealth bomber was an accident.

Relations were again ruptured abruptly in April 2001, just months after Rumsfeld took office, over the disputed circumstances in which a Chinese fighter jet collided in midair with a U.S. Navy EP-3 surveillance plane.

The Navy plane was so badly damaged that it made an emergency landing on China’s Hainan Island. The Chinese pilot died and the U.S. crew of 24 was detained by the Chinese military for 11 days. China refused to allow U.S. officials to fix the Navy plane and fly it off the island; eventually it was shipped home in pieces.

Kurt Campbell, who was deputy assistant secretary of defense for Asia and Pacific affairs during the Clinton administration, said in an interview that Rumsfeld’s visit is a welcome change of approach for the Bush administration.

Some think Rumsfeld chose to go to China now because U.S. allies in Asia have expressed concern that the U.S. is preoccupied with the wars in Iraq and Afghanistan at the expense of developments in Asia.

“I think others might suggest he just ran out of excuses why he hasn’t gone” earlier, Campbell said.

Rumsfeld’s itinerary includes stops in longtime U.S. ally South Korea as well as Mongolia, a newfound partner in Bush’s global war on terrorism. Rumsfeld also will stop in Kazakhstan and Lithuania.

AP-ES-10-15-05 1333EDT