The warnings came both from Chinese President Hu Jintao and a spokesman for the Chinese parliament, who also announced a hefty increase in China's 2008 defense budget.
Speaking to the 11th National Committee of the Chinese People's Political Consultative Conference in Beijing, Hu said, "The Taiwan independence activities have run counter to the Chinese nation's strong will to safeguard national unity. Such activities will get nowhere and are doomed to fail," Xinhua news agency reported.
Separately, Jiang Enzhu, spokesman for this year's session of the National People's Congress, said Taiwanese President Chen Shui-bian and others are destined to "pay a dear price" if they "stubbornly take the dangerous path of Taiwan independence."
Jiang also announced China's defense budget for 2008 will be up 17.6 percent from last year to more than $58 billion.
On Taiwan, which China sees as a breakaway province, Jiang said the referendum on U.N. membership sought by Chen would amount to seeking "de jure independence" of Taiwan, which will seriously harm the peace and stability in the Taiwan Straits.
The Taiwan referendum expected soon would ask Taiwanese whether they want membership in the United Nations under the name of Taiwan instead of its current Republic of China.
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