The commander of U.S. forces in the Pacific is meeting with Chinese officials in Beijing Monday to discuss military ties, Taiwan and other issues.
Admiral Timothy Keating, head of the U.S. Pacific Command, met Chinese Foreign Minister Yang Jiechi behind closed doors.
The official Xinhua news agency said Yang demanded that the United States not allow Taiwan President Chen Shui-bian to engage in any separatist activities by using U.S. territory.
Xinhua said the remarks were in reaction to Mr. Chen's stopover in Alaska on Sunday.
Keating is also expected to meet with Vice Chairman of the Central Military Commission Guo Boxiong, before touring military facilities in Shanghai and Guangzhou during his three-day visit.
The admiral arrived in Beijing Sunday on his second trip to China since being appointed to his post in March.
U.S.-China military relations came under strain in November when Beijing canceled a port call by a U.S. Navy battle group to Hong Kong. U.S. military officials said they were surprised and upset by Beijing's decision.
The aircraft carrier USS Kitty Hawk and its accompanying vessels had long been scheduled to stop in Hong Kong for the U.S. Thanksgiving Day holiday November 22.
Xinhua quoted China's Defense Ministry as saying it hopes Admiral Keating's visit will enhance understanding and boost cooperation with the U.S. military. Keating's last trip to China was in May.
A separate U.S. delegation is due to arrive for talks later in the week. The talks will be led by U.S. Deputy Secretary of State John Negroponte and Chinese Deputy Foreign Minister Dai Bingguo.
Some information for this report was provided by AFP and AP.