U.S. Defense Secretary Robert Gates complained at a security forum in Singapore over the weekend about China's turning down his request for a visit to Beijing during his Asia tour, claiming that China's attitude "makes little sense."

There is no official confirmation from the Chinese side of Gates' complaint. But judging from a sequence of events, it is obviously not China, but the United States that should be blamed for the setback in bilateral military ties.

Military-to-military relations between China and the United States have been chilled since Washington decided in January to sell 6.4 billion U.S. dollars' worth of military hardware to Taiwan, including the advanced PAC-3 air defense missile system.

At the forum, General Ma Xiaotian, deputy chief of general staff of the Chinese People's Liberation Army, made it clear that main obstacles exist in the development of bilateral military relations.

He mentioned the arms sales to Taiwan as well as frequent reconnaissance operations by the U.S. naval ships and aircraft in the waters and airspace of China's exclusive economic zones and U.S. legislation's restrictions on bilateral military exchanges.

As General Ma stressed, "the barriers between U.S.-China military relations are not built by China."

However, Gates' description of the arms sales as "nothing new" betrayed his insufficient understanding of the severity of the issue, which is not just an ordinary, but a serious problem disturbing the U.S.-China relations over the past 30 years.

The Taiwan issue concerns China's sovereignty and territorial integrity and its core interests. In a speech to the opening session of the second round of China-U.S. Strategic and Economic Dialogue in May, Chinese President Hu Jintao said China and the United States should respect each other's core interests and major concerns.

Sovereignty, independence and territorial integrity are a country's most basic rights recognized by the norms governing international relations, and to the Chinese people, nothing is more important than safeguarding national sovereignty and territorial integrity, Hu said.

According the U.S.-China joint communique of Aug. 17, 1982, Washington promised it would gradually reduce the level of arms sales to Taiwan, the quality and quantity of the arms sales to Taiwan will not exceed the previous level, and will eventually figure out ways to resolve the issue.

Regrettably, the United States has not fulfilled its obligations and continued its arms sales to Taiwan despite protests from China. As a result, since the establishment of bilateral relations, the high level China-U.S. military exchanges have been in what General Ma calls a strange cycle of "development, standstill, another development, another standstill."

China and the United States increasingly need each other to tackle challenges facing both countries and the world, which calls for close and sustained cooperation in military as well as political and economic fields.

But to achieve such kind of cooperation, it does make sense for the United States to show more understanding and respect for the feelings of the Chinese people on issues of its core interests.