The United States is having some success encouraging China to be more transparent about its military, the top U.S. commander in the Pacific said yesterday.

But Adm. William Fallon said Beijing would need to open up further before he'll suggest that Congress loosen restrictions on military contact between the two Pacific powers.

"I think we're making progress. And I'd like to see us continue to move down this path," Fallon said. "Then I'd feel more comfortable going back to Washington and recommending they make some adjustments."

U.S. law limits exposure of the Chinese military to certain U.S. operational areas and requires the U.S. military to submit annual reports of its contacts with the People's Liberation Army.

Fallon has pushed to increase bilateral military contacts since he assumed control of the Pacific Command in February last year, saying the two countries must understand each other to avoid miscalculation.

Military ties between the United States and China deteriorated after a U.S. Navy spy plane and a Chinese fighter jet collided off China's southern coast in 2001.

Fallon, along with Defense Secretary Donald Rumsfeld and other officials, has repeatedly called on China to explain why it is rapidly modernizing its military and has boosted its annual military spending by double-digit percentages for about a decade.

Some U.S. critics have labeled as naive Fallon's efforts to boost ties with China's military, charging it exposes the U.S. military to examination by China without ensuring U.S. officers win the same access to China's forces.

Fallon countered it would be irresponsible for him to not work with China.

"I can only ask, so what would they have us do? Just sit here and be a sphinx?" he said. "It's in the interests of our country to engage with these people and not just stick our heads in the sand and just find things to quibble over."

Fallon said he was not blind to potential security challenges from China. "Having spent 39 years in uniform in military service, I think I'm at least sensitive to the potential for things maybe not going the way we'd like to see them. We take the prudent precautions necessary," he said.

Rumsfeld approved increasing exchanges last October during a visit to Beijing. Since then, a delegation of Chinese officers has visited military bases in Hawai'i and Alaska, and another Chinese group visited Camp Smith to see how the Pacific Command handled administrative tasks.

A delegation of Pacific Command officers has visited China, while Fallon himself traveled there in May for a week of meetings and military installation tours.

Fallon said it was "a start" that China accepted his invitation to observe exercises the U.S. military plans to hold off Guam next week. Three aircraft carriers will be operating together in the Pacific for the first time since the Vietnam War.

"We take the step to invite them," Fallon said. "There's an expectation that they will reciprocate."