A senior U.S. arms control official said Monday that, despite past sales of nuclear-related technology, the Chinese government now seems committed to cooperating with the United States to prevent nuclear proliferation in North Korea and elsewhere. The upbeat assessment from John R. Bolton, undersecretary of state for arms control and international security, seemed designed to take the edge off reports from Washington this weekend quoting U.S. officials saying China has been — and may still be — cooperating with Pakistan on nuclear technology and missile development. “We are engaged in a continuous dialogue with China about what I think is a commitment at the top levels of the Chinese government to prevent the spread of weapons of mass destruction,” Bolton said at a news conference here after the first of two days of talks with Chinese officials. Full Story