U.S. Defense Secretary Jim Mattis on Tuesday became the first Pentagon chief to visit China since 2014, starting a three-day trip with a goal of improving security dialogue with Beijing despite increasingly fraught Sino-U.S. relations.
Mattis, a former Marine general, has been highly critical of China's muscular military moves in the South China Sea. The U.S. military even withdrew an invitation to China to join a multinational naval exercise which will start during Mattis' visit, upsetting Beijing.
The trip comes against the backdrop of spiraling tensions between Beijing and Washington over trade. Beijing is also suspicious of U.S. intentions toward self-governing and democratic Taiwan, which is armed by the United States, though China views the island as a sacred part of its territory.