Chinese and American officials have finished a day of talks about the spread of missile technology and the launch of commercial satellites.
Chinese officials say they asked the United States to stop blocking the launch of American-made commercial satellites on Chinese rockets. Beijing says the United States agreed last November to allow the launches.
U.S. embassy officials have said almost nothing about the talks, but when Secretary of State Colin Powell visited Beijing last month, he said the two sides would focus on nonproliferation issues.
The U.S. negotiators are led by State Department official Vann Van Diepen and include Pentagon technical experts as well as diplomats.
The Americans were expected to complain that China allegedly sent missile technology to Pakistan in violation of the November agreement. China and the government-owned company named in the allegation both deny the charge.
The allegation surfaced in a newspaper report and was repeated by a delegation of U.S. Senators who met with China's President earlier this month.
Official Chinese media have called the weapons proliferation issue one of the most difficult in the sometimes strained relationship between Washington and Beijing.
Chinese newspapers also say Beijing is concerned about U.S. weapons sales to Taiwan. China considers the island a renegade province and regards the weapons sales as violations of its sovereignty.