5. January 1998, July 2000: William Cohen

"Throughout good times and bad, we always maintain the ability to have constructive dialogue and to be able to sit across from one another to discuss issues openly, frankly, honestly and in a very positive and constructive dialogue," Cohen said while visiting the Ministry of National Defense of China in 1998.

Cohen's visit in 2000 was his first since China-US bilateral ties were severed following the 1999 bombing of the Chinese embassy in Belgrade, Yugoslavia, during a NATO joint operation.

6. October 2005: Donald Rumsfeld

"Over the years, of course, the US-China relationship has encountered some challenges, to be sure, but challenges also offer opportunities - opportunities to learn from each other," Rumsfeld said during a visit to China. After the midair collision by Chinese and American aircraft in April 2001, the US Department of Defense announced a unilateral suspension of all military exchanges between two countries. This was ended by Rumsfeld's China trip, and he became the first senior US official to visit the headquarters of the Second Artillery Corps of China.