U.S. Defense Secretary Robert Gates says China's military appears to be reluctant to engage in a high-level dialogue with the United States.

Gates said Thursday the People's Liberation Army is "significantly less interested" in developing U.S. ties than China's political leaders. He was speaking to reporters on a flight to Singapore where he is attending a regional security conference.

U.S. officials say Gates had hoped to travel to China after the conference to discuss reviving military exchanges, but Beijing informed him the timing of such a visit was "not convenient." Gates said he was disappointed by China's decision.

The Chinese military's deputy chief of staff, General Ma Xiaotian, said last month U.S. weapons sales to Taiwan remain the biggest obstacle to military ties. The Obama administration decided in January to allow a major arms sale to the island to go ahead.

Gates said Thursday such deals go back years and have not affected the development of political and economic ties between the United States and China.

Some information for this report was provided by AP, AFP and Reuters.