The ongoing visit of US defense Secretary Robert Gates to Beijing is widely perceived as a clear signal of improving China-US military ties, which as a barometer of bilateral relations, will contribute to the current warm climate between the two countries.

Gates held talks with China's Defense Minister Liang Guanglie on Monday and this is the second meeting between the two defense chiefs in about two months. It is expected that in-depth discussions and consultations between officials on both sides will deepen mutual understanding and help dispel distrust and even suspicion between the two militaries.

Gates' visit, which started on Sunday, has come days before Chinese President Hu Jintao's trip to the United States. High-level exchanges before Hu's US trip will pave the way for a successful visit.

Military exchanges between Beijing and Washington hit a low ebb last year after the latter approved a multi-billion arms package to Taiwan, an inalienable part of China, in January 2010. In protest at such a reckless move by the United States, Beijing temporarily suspended exchange programs between the two militaries.

Compared to thriving trade ties and generally stable political ties, China-US military ties tend to be a lame duck. As two important players in both world and regional affairs, China and the US should put their military exchanges back on track as soon as possible.

Even though the US defense chief's presence in Beijing marks a positive development in normalizing bilateral military ties, it would be too optimistic to conclude that military exchanges between Beijing and Washington will be plain sailing after a single visit.

Obstacles, some major, still stand in the way of normal military relations between the two countries. The US arms sales to Taiwan, which have been ongoing for more than 30 years, are the biggest impediment, but intensive reconnaissance and surveillance of the Chinese mainland from the South China Sea and East China Sea and Washington's growing penchant for projecting its military power in the Asia Pacific have also sowed the seeds of distrust between the two militaries.

If the Pentagon really cares about building stronger ties between the two militaries, it should show sincerity in removing these obstacles. Regrettably, the US finds faults in China's so-called military buildup from time to time, turning a deaf ear to China's repeated explanation that its military modernization is purely defensive.

It is obvious that strategic mutual trust between the two defense forces remains low. Both Washington and Beijing should make efforts to build strategic mutual trust. This is in the interests of both countries and conducive to world peace and stability too. Both sides should understand that lack of mutual strategic trust could lead to dangerous consequences.