China says trade with political rival Taiwan surpassed a record $100 billion last year despite occasional tensions over China's claim to the self-run island. But, a government spokesman warned business relations could sour if Taiwan seeks to alter its political status. Daniel Schearf reports from Beijing.

Ships and boats sail on Huangpu River in front of skyscrapers in Pudong New Developing Zone in Shanghai (file photo)

China's Taiwan Affairs Office said Wednesday that trade between the two in 2006 rose 18 percent to a record $107.8 billion.

Officials said Taiwanese businessmen invested more than $3 billion in the mainland last year. Imports from Taiwan rose 16 percent while China's exports to the island were up 25 percent.

Tourist flows also soared, with more than four million Taiwanese having visited mainland China and over 200,000 mainlanders going to Taiwan.

Despite booming economic ties, the office's spokesman, Yang Yi, warns cross-strait relations would face severe challenges in 2007 if Taiwan seeks to change its constitution.

"We will sincerely and with utmost efforts strive for the prospect of peaceful reunification," said Yang. "But we cannot tolerate Taiwan independence and cannot allow any people or any means separate Taiwan from China."

Taiwan's independence-leaning President Chen Shui-bian has said he wants the island to adopt a new constitution.

But Beijing is concerned Mr. Chen may try to alter Taiwan's status.

Taiwan and China split after Nationalist forces lost China's civil war to the Communists in 1949 and fled to Taiwan. In the past, both sides claimed sovereignty over the other, but now only China continues to actively and sometimes threateningly voice its claim.

Beijing in 2005 passed a law authorizing the use of force against Taiwan if the island moves toward formally declaring independence.

Even though political tensions sometimes run high, in recent years commercial and law enforcement cooperation has improved.

Last week, Chinese police tracked down a Taiwanese man suspected of robbing an armored car in Taipei. Yang said Wednesday the suspect would be sent back to Taiwan.

Taiwan authorities also have asked China to return a fugitive wanted for his role in a financial scandal.

Wang You-theng, chairman of the Rebar Group, is wanted in Taiwan on embezzlement and insider trading charges.

But, Yang said Wang had left the mainland before Taiwan issued the arrest warrant.