LOOKING AHEAD: Mike Mullen visits a PLA Air Force base in Jining, east China's Shandong Province, with Ma Xiaotian, Deputy Chief of the General Staff of the PLA on July 12 (XING GUANGLI)

At the same time, Mullen reached out to young Chinese by delivering a speech, titled "Cooperative Security and Regional Stability in Asia," at the Renmin University of China in Beijing and answering students' questions.

Commenting on his China trip, Mullen said exchanges between Chinese and U.S. military officials have helped "clear up the lack of transparency."

"We are just beginning," he said. "The relationship is just recently renewed. So we have a long way to go, and the leaders are very committed to that. I'm actually very confident in the future of the military-to-military relationship."

Communication

During Mullen's visit, military leaders of both sides didn't avoid sensitive issues, such as the South China Sea, U.S. surveillance operations in waters near the Chinese coastline and U.S. arms sales to Taiwan, said Meng Xiangqing, a professor with the PLA National Defense University in Beijing.

This reflects the fact that military relations between China and the United States are maturing, just as in interpersonal exchanges—when two persons become more familiar, they talk in a more frank way and tend to put their differences on the table, Meng said.

It is "inappropriate" for the United States to participate in military drills in the South China Sea, as China and a number of Southeast Asian countries are embroiled in disputes over the region, Chen said after holding talks with Mullen on July 11.

Several Southeast Asian states, including the Philippines and Viet Nam, have asserted claims over the oil- and gas-rich South China Sea. But history shows China has indisputable sovereignty over the sea's islands and their surrounding waters.

HANDS ON: Mike Mullen in the cockpit of a Chinese fighter aircraft (XING GUANGLI)

Though the United States has said on many occasions it has no intention of interfering in South China Sea disputes, it has continued to hold military drills in the region, he said.

The United States conducted an 11-day joint military exercise near the South China Sea with the Philippines beginning June 28 and is planning to hold joint naval activities with Viet Nam in July.

China's position on the South China Sea is consistent and clear. It believes disputes over the region should be solved through negotiations, Chen said.

On U.S. surveillance operations in waters near the Chinese coastline, Chen said China is a responsible country and there is no need for the United States to conduct frequent surveillance on China. Surveillance activities can only create obstacles for Sino-U.S. military cooperation.

The two sides didn't go any further on the South China Sea issue, but expressed their respective positions, said CASS' Tao.

Despite glaring differences, both sides are fully aware of the importance of Sino-U.S. relations. That's why they have been able to cooperate in areas where they have common interests and communicate with each other on contentious issues, Tao said.

In the coming months, more exchanges are slated to take place between Chinese and U.S. armed forces. According to a consensus reached between Chen and Mullen, the commander of one of the PLA's military regions will visit the headquarters of the U.S. Pacific Command in the third quarter of this year. The commander in chief of the U.S. Pacific Command will visit China by the end of the year.

Hospital ships of Chinese and U.S. navies will carry out joint medical and rescue drills. The two navies will also conduct anti-piracy drills in the Gulf of Aden in the fourth quarter of this year. Armed forces of both sides will conduct humanitarian rescue and disaster relief drills in the third quarter of next year.