US-Chinese relations are at risk after Washington announced plans to sell arms to Taiwan, according to official sources in Beijing.

Chinese Foreign Minister Yang Jiechi has become the most senior Beijing official to denounce the $6.4bn package that Washington says is part of its commitment to protect Taiwan.

Jiechi said that Washington had ignored Beijing’s demands to halt the sales despite many rounds of discussions.

The US should “truly respect China’s core interests and major concerns, and immediately rescind the mistaken decision to sell arms to Taiwan, and stop selling arms to Taiwan to avoid damaging broader China-US relations,” Jiechi said.

Diplomatic negotiations between the two permanent members of the UN Security Council could also be damaged on the grounds of US weaponry sales to Taiwan, according to several news agencies.

In addition, the US may lose China’s backing in its nuclear stand-offs with Iran and North Korea, reports Xinhua news agency.

The sales will negatively influence China-US exchanges and cooperation in important areas, and will lead to consequences that neither side wishes to see, the report said.

China said it would postpone or halt military exchanges to Taiwan, including scheduled visits for 2010.

The US arms sale to Taiwan may push China, for the first time, to impose sanctions on companies selling arms to the island.

The proposed arms sale to Taiwan would include Black Hawk utility helicopters built by Sikorsky Aircraft; Lockheed Martin-built and Raytheon co-integrated Patriot missile defences and Harpoon land and sea attack missiles built by Boeing.