BEIJING, July 16 (Xinhua) -- Guo Boxiong, vice chairman of China's Central Military Commission (CMC), left Beijing Sunday evening for a visit to the United States, the latest sign of closer ties between the two armed forces.

　　Invited by U.S. Defense Secretary Donald Rumsfeld, Guo is the highest-ranking military officer to visit the United States since 2001.

　　Guo ranks the second to Chairman Hu Jintao in the 11-member CMC, China's top military authority.

　　China-U.S. military ties were broken off in 2001 when a Chinese fighter aircraft was damaged by a U.S. surveillance plane over the South China Sea.

　　Guo's visit comes when China-U.S. military relations are "at the best since 2001," said Qian Lihua, deputy director of Foreign Affairs Office of Chinese Defense Ministry.

　　Qian said Guo's U.S. visit is "the most important Chinese military exchange with another country this year".

　　During his stay in Washington, Guo is scheduled to hold talks with Rumsfeld on a wide range of issues, including international and regional security, and China-U.S. military ties. He will also meet with other members of the U.S. administration.

　　In addition, the week-long U.S. visit will take Guo to U.S. military bases and institutions.

　　Analysts say cooperative agreements on specific fields might come out of Guo's U.S. visit.

　　"Guo's visit will help promote China-U.S. strategic trust on traditional security, and expand cooperation on non-traditional security fields," said Yang Yi, director of Institute for Strategic Studies at the National Defense University of China.

　　Among Guo's entourage are Political Commissar of Chinese People's Liberation Army (PLA) Nanjing Military Area Command Lei Mingqiu, Assistant to the PLA Chief of the General Staff Zhang Qinsheng, Deputy Commander of PLA Navy Zhao Xingfa, Deputy Commander of PLA Air Force Liu Chengjun, and Chief of Staff of PLA Second Artillery Force Yu Jixun.

　　Guo's visit is part of the growing high-level visits between Chinese and U.S. armed forces over the past years.

　　Chinese Defense Minister Cao Gangchuan and PLA Chief of General Staff Liang Guanglie visited the United States respectively in 2003 and 2004.

　　Last October, Rumsfeld paid an official visit to China, his first since taking office in 2001. During his stay in Beijing, Rumsfeld visited the PLA Second Artillery Force, which was for the first time opened to a foreign military leader.

　　William Fallon, commander of U.S. forces in the Pacific, paid two visits to China in September 2005 and May 2006.

　　Fallon also invited a Chinese delegation to observe a U.S. military exercise in Guam in June, the first invitation of its kind extended by the United States.

　　An exchange mechanism of multi-level officers between the two armed forces are in place. Military institutions in China and the United States have regular exchange programs.

　　The defense departments of the two countries have restored a series of consultation mechanism on maritime security, humanitarian disaster relief and military environmental protection.

　　Last month, a U.S. delegation, headed by Assistant Defense Secretary Peter Rodman, came to Beijing for the eighth annual round of defense consultation.

　　"Both sides had a number of specific ideas of new areas of cooperation or new activities," Rodman said after the consultation.

　　Also last month, the flagship of U.S. Navy's Pacific fleet "Blue Ridge" paid its fourth visit to China's economic hub Shanghai, highlighting warming exchanges between the two navies.

　　However, officials with the Chinese Defense Ministry said there remain some "obstacles" preventing China-U.S. military ties from going forward, such as the long-standing Taiwan issue and U.S. strategic distrust for China.

　　The U.S. congress passed some bills limiting military exchanges with China, as represented by the 2000 Fiscal Year Defense Authorization Act.

　　"From an overall point of view, positive factors in China-U.S, military ties outweigh negative ones," said Qian, the official with the Chinese Defense Ministry.

　　As long as the two countries view the bilateral ties "from a strategic and long-term perspective", respect each other and properly address mutual concerns, the good momentum of the military ties will go on, Qian said.

　　Following his U.S. tour, Guo will pay an official visit to France as guest of French Defense Minister Michele Alliot-Marie.