US President George W Bush has warned Taiwan against any steps towards independence, after talks with the Chinese prime minister in Washington.
The two leaders held talks in the Oval Office
Taiwan's president is planning a referendum next year to ask people if they feel threatened by China's military posture towards the island.
The US sees the vote as a move towards independence, a view shared by China.
After talks, Mr Bush made clear the US is against any unilateral moves which threaten its 'one China' policy.
Speaking to reporters in the Oval Office of the White House after a 40-minute meeting with Prime Minister Wen Jiabao, Mr Bush said: "The United States' policy is one China.
"We oppose any unilateral decision by either China or
Taiwan to change the status quo, and the
comments and actions made by the leader of Taiwan indicate
that he may be willing to make decisions unilaterally, to
change the status quo, which we oppose."
Correspondents say his comments were the US administration's strongest statement to date in opposition to the referendum.
But White House officials insist that criticism of Taiwan should not be seen as a "green light" for
Beijing to intimidate the island with its military might.
Taiwan President Chen Shui-bian - leader of the pro-independence Democratic Progressive Party - says the proposed "anti-missile, anti-war" referendum is aimed at asking China to dismantle hundreds of ballistic missiles
targeting the island.
Beijing regards Taiwan as a renegade province, but Mr Wen said China's goal was to pursue
peaceful reunification with Taiwan.
"Stability can only be maintained through unswerving
opposition to pro-independence activities," he said.
Mr Wen accused the Taiwanese leaders of "using democracy as an excuse and attempt to resort to defensive referendums to split
Taiwan away from China".
He added: "Such separatist
activities are what the Chinese side can absolutely not
In his comments on Tuesday, Mr Bush also expressed his appreciation of China's role in convening talks to resolve the stand-off between North Korea and its neighbours over the secretive communist state's nuclear weapons programme.
"The goal is to dismantle a nuclear weapons program in a
verifiable and irreversible way, and that is a clear
message that we are sending to the North Koreans," he
"We will continue to work with China and the other
countries involved to solve this issue peacefully."
Mr Bush has urged the Chinese Government to fully integrate into the rules and norms of the international financial system.
In particular, the Americans are calling on China to make its exchange rates more flexible and buy more of their goods.
In response to a question on trade disputes, Mr Wen said
China had been taking steps to reduce the massive US
trade deficit with China.