America's top military officer toured military bases on China's east coast Tuesday, on the third day of a high-profile visit aimed at improving military cooperation.

Admiral Mike Mullen, chairman of the U.S. Joint Chiefs of Staff, visited an air base in Shandong province and was to continue later to a base in Zhejiang province. The official Xinhua news agency said he attended an air show at the Shandong base, which is equipped mainly with Su-27 fighters.

The tour followed a day of intense diplomacy Monday in Beijing, where Mullen discussed measures to deepen mutual trust with Chinese Vice President Xi Jinping. Xi hailed what are widely seen as improving Sino-U.S. ties, saying they represent one of the world's most important bilateral relationships.

Mullen concludes his China tour Wednesday before continuing on to South Korea and Japan. In South Korea he will attend the inauguration of General James Thurman as the new commander of U.S. forces in the country.

Earlier Monday, China's military chief, General Chen Bingde, criticized the timing of U.S. naval exercises in the South China Sea and surveillance flights off its shores.

Speaking alongside Mullen, Chen said the maneuvers with the Philippines and Vietnam were “extremely inappropriate” at a time when China is embroiled in tense territorial disputes with both countries.

Mullen responded that the United States has been staging drills with its friends and allies in the region for decades and will continue to do so. He said the United States will also continue the surveillance flights, which are within “international norms.”

General Chen also said the U.S. is spending too much on its military and is putting too much pressure on American taxpayers in the wake of the global economic crisis.