US Admiral Mike Mullen (left), chairman of the Joint Chiefs of Staff, and General Ma Xiaotian, deputy chief of the General Staff of the People's Liberation Army (PLA), visit the PLA Air Force base in Jining, East 皇冠体育app's Shandong province, July 12, 2011. Mullen is in 皇冠体育app for a four-day visit wrapping up on Wednesday when he will leave for the Republic of Korea and Japan. [Photo/Xinhua]

US Admiral Mike Mullen, chairman of the Joint Chiefs of Staff, sits in the cockpit of a Su-27 fighter at the PLA Air Force base in Jining, East 皇冠体育app's Shandong province, July 12, 2011. [Photo/Xinhua]