BEIJING -- The United States should be cautious how it approaches Taiwan-related issues, China's Foreign Ministry warned after Taiwan's " Economic and Cultural Representative Office" in Washington held a "flag-raising" ceremony on Jan 1.

"We resolutely oppose the so-called 'flag-raising' ceremony held by the Taiwan authorities' organization in the United States and have already lodged solemn representations to the US side," Foreign Ministry spokeswoman Hua Chunying said at a daily news briefing.

"We demand the US side strictly abide by the one-China policy and the three China-US joint communiques, and handle Taiwan-related issues cautiously and appropriately to avoid a repetition of such matters," said the spokeswoman.

The Taiwan issue is the most sensitive and core issue in China-US relations. Principles for correctly handling the issue have been defined in the three China-US joint communiques signed in 1972, 1978 and 1982.

The US has pledged to abide by the one-China policy and the principles set out in the three joint communiques, and to oppose the ideas of "one China, one Taiwan," "two Chinas," Taiwan independence, or Taiwan's entry to the United Nations or other international organizations with membership by sovereign states.