Mexico has withdrawn from a trade fair in Shanghai scheduled for next week. The decision follows a dispute with China about the treatment of Mexicans amid the A(H1N1) flu outbreak, organizers said yesterday.

"Our headquarters informed me this morning of Mexico's decision to quit the trade fair," said Hou Xu, marketing director of SIAL China, a large food and beverage exhibition running from May 19 to 21.

The Associated Press has reported that Mexico said the treatment of its citizens was "unacceptable".

Mexican officials also complained China withdrew their country's "guest of honor" status for the fair, AP reported.

"The recently adopted measures by fair organizers and the Chinese government are unacceptable," said ProMexico, the Mexican government's agency that promotes foreign trade.

Thirty Mexican companies had planned to participate, AP said.

The Mexican withdrawal from the fair followed China's earlier cancellation of flights to Mexico and the banning of pork imports from Mexico.

Medical expert Zhong Nanshan said last week that the quarantine measures adopted by China against HIN1 flu were necessary.

People from impacted areas need to be quarantined for a certain period to check whether they are infected, Zhong was quoted as saying by Yangcheng Evening News' website.

"Overall, the WHO feels that China has prepared itself well for this outbreak situation," said Vivian Tan, WHO China's communications officer.

“The virus has already spread to a number of countries. What is important now is to try to limit the spread locally through early detection of cases and early treatment,” Tan said.

International relations analysts said the dispute would not affect national-level relations between China and Mexico.

"It's on a certain condition that Mexico made these responses. It won't impact bilateral relations," said Huang Shikang, former Chinese ambassador to Mexico.

Pang Zhongying, an international relations expert at Renmin University of China, said China's measures were "not discriminatory" against Mexicans because the country has also quarantined Chinese people returning from Mexico.