Chinese President Hu Jintao stressed his strong opposition to Washington's military support for Taiwan during a telephone conversation with President Bush on Friday.
The Chinese Foreign Ministry says President Hu told Mr. Bush that Beijing will never tolerate Taiwanese independence, and cannot allow anyone to split Taiwan from the Mainland.
In a statement that appeared on its Web site Saturday, the foreign ministry said the Chinese leader expressed concerns that U.S. weapons sales to Taiwan could aggravate an already sensitive situation.
Taipei is currently reviewing plans to purchase $18 billion worth of U.S. weapons systems and military aircraft.
A White House spokesman, talking to reporters on Friday, said that during the conversation President Bush reaffirmed Washington's commitment to a "one-China" policy during the telephone exchange.
The United States recognizes China's claim to Taiwan, but under the Taiwan Relations Act, Washington supplies the island with military equipment and defensive support.
Professor Philip Yang of Taiwan National University says the weapons sales are only part of a broader concern in Beijing that U.S. support could encourage Taiwan's pro-independence movement.
"The true intention [of Beijing] is to ask Bush to stick to the one-China principal on the one hand, and on the other hand try to prevent Taiwan from unilaterally changing the status quo, so I think United States gets the message," he said.
President Hu's statements come at a tense time in Beijing-Taipei relations.
Both Taiwan and China held extensive military exercises earlier this month. And on Thursday, a Chinese official said Taiwan President Chen Shui-bian's plans to rewrite Taiwan's constitution could be considered grounds for war.
Professor Yang says Beijing's hard line reflects concerns over the recent re-election of President Chen, who favors independence for the island.
"Although in his inauguration speech he's promised he will not touch upon sovereignty issues, but leaders in Beijing just don't trust him and they worry that he probably just in fact [is] pushing forward to another step of creeping Taiwan independence," he said.
Mr. Bush, who according to the White House initiated the Friday evening telephone conversation, recently called on both countries to ease tensions and avoid direct confrontation.