Chinese Foreign Ministry spokesperson Hua Chuying said in an online statement late Sunday, that solemn representations have been lodged with the US.

Earlier this month, China's Defense Ministry said that the US Congress had disregarded the bigger picture of Sino-US relations by passing the act, and China reserved the right to take further measures.

In the 1982 communique,China and the US agreed that the latter would only maintain unofficial relations with Taiwan, and that the question of Taiwan is a matter belonging to China's internal affairs.

The US had also promised to gradually minimize military contact with Taiwan. But last year - reached a billion-dollar arms sale to Taiwan. In regards to the act, viewed as the latest affront to China's core interest, experts say even though it only expresses an opinion of  US congress, the action could still have serious implications to bilateral relations.