China expressed firm opposition on Tuesday to any visit by "Taiwan independence" separatist forces to countries that have diplomatic relations with China under any pretext.

Foreign Ministry spokeswoman Mao Ning made the remarks when asked about former Taiwan leader Tsai Ing-wen's upcoming visit to the Czech Republic this month.

Tsai, who stepped down in May, will visit Prague and deliver a speech at a Forum 2000 Conference which begins on Oct 13, three sources briefed on the matter told Reuters.

Tsai's European tour will also include stops in France and Belgium, according to media reports.

The spokeswoman urged Czech and other relevant countries to adhere to the one-China principle, and respect China's sovereignty and territorial integrity.

She urged the countries to refrain from providing convenience to "Taiwan independence" separatist forces and avoid damaging bilateral ties.

Mao also warned the Democratic Progressive Party authorities that seeking independence is a dead end.

"Any political manipulation or attempts to seek independence by soliciting external support will be futile," she said.

China has been demanding other nations not to have official contact with the island, which is an inalienable part of China.

Chen Binhua, a spokesman for the Taiwan Affairs Office of the State Council, blasted the DPP authorities for seeking external support by flattering foreign forces in order to pursue "independence" at a news briefing last week.

He warned the DPP authorities that no matter how many weapons they acquire from the United States, it will not shake the Chinese mainland's firm resolve to resolve the Taiwan question and achieve national reunification, nor will it hinder the mainland's strong capability to thwart "Taiwan independence" schemes and safeguard national sovereignty.