China (search) warned Sunday that Taiwan is stirring "new tension" with Beijing (search), a day after hundreds of thousands of Taiwanese marched in protest against the communist mainland's threats to take their self-ruling island by force.

Vowing never to back down, China said via government media that it stood by its controversial anti-secession law passed March 14, which authorizes an attack on Taiwan if the island moves toward formal independence.

"The extreme Taiwan independence secessionists have been malevolently distorting the principles of the law to misguide the Taiwan people and instigate antagonism and create new tension across the Taiwan Strait," the commentary said. It was printed in official newspapers and read on state television.

The two sides split in 1949 amid civil war, but China insists that democratically ruled Taiwan is part of its territory. It forbids its diplomatic partners from recognizing Taiwan's government and prevents Taiwan from joining international organizations like the United Nations.

Taiwan's protesters Saturday said they wouldn't be silenced by Beijing. "What do we want from China? Peace," they chanted.

Organizers said one million people took part. Taiwan's opposition Nationalist Party (search), which is against independence, stayed away.

China's completely government-controlled media portrayed the march as "political carnival" and a waste of money that caused traffic jams.

"Taiwan independence march is an empty show of strength," read a headline in the Beijing Morning Post.

The newspapers didn't carry pictures of the march. CNN and BBC broadcasts, only available at hotels and apartment complexes for foreigners, were blacked out when they reported on the protest.

Beijing is worried that Taiwan is drifting toward formal independence. The anti-secession law codifies the use of military force if the island seeks a permanent split.

U.S. Secretary of State Condoleezza Rice (search) said while in Beijing last week that the law has aggravated the Taiwan situation.

The law is also affecting the European Union's debate over whether to lift its 15-year-old arms embargo on China. The EU had appeared close to lifting the ban, but British Foreign Secretary Jack Straw said China's potential use of force has created "quite a difficult political environment."

In Taiwan, a senior official said China should try to ease worries about the law.

"They should try to get the message of the demonstration," said Chiu Tai-san, vice chairman of the Mainland Affairs Council. "The direction of future cross-Strait relations depends on what action the Chinese communists will take."

Taiwan's China Times newspaper described the protest as a "contemporary epic" that has highlighted the Taiwanese identity as separate from China.