Beijing said on Thursday that the United States sending acting military serviceman to Taiwan under any pretext will undermine bilateral ties, urging Washington to change course.

Foreign Ministry spokesman Geng Shuang made the remarks after a Taipei Office of the American Institute in Taiwan?(AIT) spokesperson confirmed Wednesday that the US Department of State has stationed acting military personnel at AIT since 2005.

The US is set to do so for the new office complex set to officially open May 6.

On the same day Voice of America quoted a US State Department spokesman saying the US recognizes the one-China policy and that the AIT Taipei office's security work is carried out by a small group of US personnel and a larger number of local employees and authorities.

"China resolutely opposes any form of official exchanges and military contacts between the US and Taiwan," Geng told a news conference.

The US has made a clear commitment to maintaining unofficial relations with Taiwan, Geng said, adding that Beijing has repeatedly stated its position on the issue to Washington.

The one-China principle is the political foundation for bilateral relations, he said, urging the US to keep its promises and to abide by the principles of the three China-US joint communiques.

"We urge the US to correct its wrong practice and prudently and properly handle Taiwan-related issues to avoid damaging China-US relations and cross-Straits peace and stability," he said.