China is warning Taiwan not to reform the island's constitution. The warning from the Communist leadership on the mainland comes as legislators on the democratically ruled island consider making changes, including re-naming the island.

Revamping the constitution has been one of Taiwan President Chen Shui-bian's main political objectives, and one that Beijing - which considers Taiwan a part of its territory - sees as a move toward independence.

Members of Chen's party are expected to introduce a bill on changing the island's name from the current "Republic of China," to "Republic of Taiwan."

China considers the change an assertion of Taiwan's separate identity and tantamount to a declaration of independence.

At a briefing in Beijing Wednesday, Li Weiyi, a spokesman of the Communist government's Taiwan Affairs Office, put Chen Shui-bian's government on notice.

"We will never tolerate their seeking to legislate independence by amending the constitution," said Li. "We will closely watch their situation and be on high alert to new developments."

China last year enacted legislation authorizing an attack on Taiwan if Beijing determines that the island is moving toward declaring formal independence.

Taiwan has been self-governed since 1949 when Chang Kai-shek's Nationalists fled there following their defeat by Mao Zedong's Communists in the Chinese civil war. The mainland government has threatened to take the island by force if necessary if Taiwan declares independence or is slow to come under Beijing's control.

The United States has pledged to help Taiwan defend itself from an attack, but has said it does not support Taiwan independence. Washington has repeatedly urged both sides to avoid taking any unilateral steps to change the status quo.

A senior State Department official this month voiced U.S. concern over China's military build-up, including the hundreds of missiles that Beijing is pointing at Taiwan. The official called on China to demonstrate more transparency in its military, and cease its arms buildup opposite Taiwan.