Wang Zaixi, vice-minister of the Taiwan Affairs Office of the State Council, said curbing Taiwan's independence crusade is the bottom line of the mainland's Taiwan policy and war will break out if the island declares formal independence.

He stressed Beijing hopes to peacefully settle the Taiwan question and does not want to have to resort to its military might as all people on the island are Chinese compatriots.

However, it should not be left to the mainland to realize the goal of peaceful reunification.

"If the Taiwan authorities collude with all splittist forces to openly engage in pro-independence activities and challenge the mainland and the one-China principle, the use of force may become unavoidable," Wang said.

"(The separatist forces) are set to pay a high cost if they think we will not use force against their conspiracy to promote formal independence."

Wang was speaking yesterday at a seminar organized by the Research Centre for Cross-Straits Relations, which was attended by scores of mainland experts on Taiwan studies.

The event was part of Beijing's efforts to counterattack Chen's recent radical separatist steps, aimed at his re-election in next year's "presidential" polls.

As a desperate voting strategy, the Taiwan leader has gone as far as to unveil his pro-independence timetable, which states the island's new "constitution" will be completed on December 10, 2006 and come into effect on May 20, 2008.

Meanwhile, Chen has also instigated his pro-independence Democratic Progressive Party to push ahead with the referendum legislation in a bid to create a legal basis for a future plebiscite on independence.

To boost the fervour of die-hard splittist members, former Taiwan leader Lee Teng-hui has even claimed that the mainland would not dare use force against the island because the United States will protect it under the Taiwan Relations Act.

Wang, however, described relying on Washington to guarantee Taiwan independence as "a very naive and extremely dangerous idea."

"The Americans will protect their own national interests but are expected to neither protect Taiwan independence nor shed blood for Taiwan independence," he said.

Xi Laiwang, a senior researcher with the China Institute of International Studies, urged the Taiwan authorities and Chen not to underestimate the mainland's determination to safeguard the sovereignty and territorial integrity of China.

"Chen's introduction of his pro-independence timetable will prompt the mainland to come up with its anti-independence timetable," he said.

"Given the imminent threat of Taiwan independence, the mainland my be forced to take pre-emptive actions to smash any splittist attempt."

In another development, Wang Daohan, president of the Association for Relations Across the Taiwan Straits, accused Chen of taking advantage of the promotion of democracy as camouflage for his separatist aim.

He said the irresponsible move of Chen's to force the pro-independence conspiracy of a handful of people upon the broad mass of Taiwan compatriots will undermine the fundamental interests of the general public.

The island's social stability and economic development will be further damaged by the separatist moves, he added.

According to former US Secretary of State Alexander Haig, Chen's actions are very dangerous.

His behaviour not only impairs the peace and stability across the Taiwan Straits but also goes against Sino-US relations, Haig said yesterday in Beijing while meeting Chinese Foreign Minister Li Zhaoxing.