Beijing has delayed some high-level military visits to the US in retaliation for Washington's proposed arms deal with Taiwan, Pentagon officials said on Tuesday.

The officials, whose names were not cited, told Reuters that China has postponed planned visits to the US by its chief of the General Staff of People's Liberation Army (PLA) Chen Bingde, as well as by one of its top regional commanders.

A planned visit to China by the commander of the US Pacific Command has also been postponed, they said.

"There are other, as yet unscheduled, events the PRC (People's Republic of China) is not considering for the time being," a Pentagon official was quoted as saying.

In its toughest response in three decades to a US arms sale to Taiwan, Beijing announced earlier this month that it would curtail military exchanges with Washington, and sanction US companies involved in the deal, and warned of the severe harm the sale would cause bilateral ties.

The Pentagon has attached great importance to military exchanges with China as it is one of the few ways for it to get really close to China's PLA which they deem mysterious.

The officials, however, said Beijing has been quite restrained. So far no visits from China are formally cancelled, while China has not imposed sanctions on any US firms involved in the arms deal as it threatened.

Beijing has also allowed a US aircraft carrier to berth in Hong Kong, a rare move during times of tension. The USS Kitty Hawk was denied entry in 2007.

When asked what actions China has taken to curb military-to-military contacts, Pentagon spokesman Bryan Whitman said: "We haven't noticed anything significant."

On the other side, the Pentagon is also seeking to play down the issue. US Defense Secretary Robert Gates said he still plans to visit China later this year.

Niu Xinchun, an expert on US studies at the China Institute of Contemporary International Relations, said so far China has not taken any major retaliatory actions, largely because of the heavily intertwined interests of the two nations.

"Anything that hurts China will ultimately hurt the US, and vice versa," he said.

Niu said he did not agree with the analysis that China's restraint is due to its expectation that the US will cancel the deal, which has yet to be approved by Congress.

"As yet it is impossible for the Congress to break the deal," he said. But it does not mean the strong dissatisfaction Beijing expressed is useless, he said.

"Actually it does not matter how heavily we make the US suffer from the incident. The key point is that we have them learn from the event that arms sales to Taiwan have deeply affected mutual trust between the two powers. We want them to realize that the loss is huge and cannot be measured by money."

"I'm sure Washington has got that point," he said.

Yin Zhuo, an admiral and senior researcher at the navy's equipment research center, said despite provocations from Washington, Beijing is still keeping calm and sticking to a long-term view on its relations with the US by allowing the US aircraft carrier to visit Hong Kong.

"And the US soldiers sent the Chinese Lunar New Year greetings to Hong Kong citizens in Cantonese, that shows the US is also trying its best to keep a good image in China."