Shanghai, China ? Taiwanese President Chen Shui-bian cranked up the heat on his mainland rivals Saturday by declaring that China and Taiwan were separate countries and that the island should hold a referendum on independence.

Chen’s remarks were the most serious such verbal provocation since his predecessor pushed the arch-enemies to the brink of war three years ago by arguing that they should deal with each other as “state to state.”

Beijing did not immediately respond to Chen’s comments, which were made during a videoconference with Taiwanese living in Japan. But observers said the statements were bound to enrage his Communist foes. They consider the island an inseparable part of China and have expressed a willingness to reclaim it by force if necessary.

“If he really supports an independence referendum, that means he is declaring war on the mainland,” said Jia Qingguo, associate dean at Beijing University’s School of International Studies. “That would be a disaster for the people of Taiwan.”

No one seemed clear about why Chen picked this moment to push Beijing’s buttons. However, politics on both sides of the Taiwan Strait might have been a factor.

Some analysts said Chen had been downplaying his radical independence stance since becoming president two years ago. But according to these observers, he has now consolidated his power within the Democratic Progressive Party and feels safer about courting the independence vote.

“He has been painfully restraining himself. At a certain time, he would explode. This seems to be the time,” said Shen Dingli, an international affairs expert at Shanghai’s Fudan University.

Chen also might have been bluffing.

He knows that Beijing faces one of its biggest leadership reshuffles in five decades of Communist rule, scheduled to take place in September at the 16th Communist Party Congress. During this sensitive period, the authorities are unlikely to take any drastic military action that would jeopardize social stability. According to this view, there could be no better time to ruffle Beijing’s feathers.