The top U.S. military officer has arrived in Beijing on a visit aimed at improving chilly military relations, AP reported. Chairman of the Joint Chiefs of Staff Adm. Mike Mullen said Sunday that sound ties are vital and the two governments should work harder on developing "strategic trust." His trip is the first of its kind in four years and part of efforts to expand ties after setbacks over U.S. arms sales to Taiwan, cyberattacks traced to China and concern about Beijing's military buildup. Mullen repeated Washington's appeal for a peaceful settlement to conflicting claims by China and its neighbors in the South China Sea.