China and Mexico Monday agreed to send chartered flights to each other's countries to fetch their citizens, dampening a row that stemmed from Beijing's quarantine of Mexican nationals in the country amid the global H1N1 flu outbreak.

On Sunday, China Southern Airlines canceled a chartered flight meant to pick up more than 200 Chinese citizens stranded in Mexico as it could not secure landing permission from Mexican airports.

The plane finally left Guangzhou for Mexico City at 10 p.m. Monday and is expected to return to Shanghai at 9 am Wednesday, the airline said.

The Mexican government Monday accused China of singling out its citizens for forced isolation despite the fact they showed no symptoms of the virus.

A Mexican embassy official said that there were nearly 70 Mexicans quarantined across China - in Beijing, Shanghai and Guangzhou.

Some had traveled to China aboard the same flight that carried an infected Mexican man - Asia's first confirmed H1N1 flu case - who is now in a Hong Kong hospital.

Mexican Foreign Minister Patricia Espinosa called China's actions "unjustified" and warned Mexicans against visiting China.

China rejected the charge, saying it was not discriminating against Mexicans and called for Mexico to be "objective and calm."

"The measures are not targeted at Mexican citizens, and are not discriminatory. This is purely a question of health inspection and quarantine," Foreign Ministry spokesman Ma Zhaoxu said Monday.

"China understands the Mexican side's concern for the rights and interests of its citizens in China, and hopes to jointly address the epidemic situation," he said.

The WHO's representative in China, Hans Troeddson, said Monday the measures taken by Beijing are proper and do not violate current regulations.

"It's really up to each country and should be in accordance with their own regulations and legislation on public health and protection of the population," he said.

Zhong Nanshan, a renowned medical expert and member of the Chinese Academy of Engineering, also defended the quarantine measures.

Medical circles are still unclear over the pathology of the H1N1 virus, he said. "We're not sure whether H1N1 carriers transfer the virus before showing symptoms," Zhong said.

As such, quarantine for a certain period is necessary to check whether those monitored are infected, he said.