A jet from Mexico landed in Shanghai today on a mission that includes stops in three other Chinese cities to bring home dozens of Mexicans quarantined under strict (A)H1N1 flu measures.

mexico swine flu pandemic outbreak 050509 02 The four-stop trip, which also takes in Beijing, Guangzhou, in the south, and Hong Kong, comes after China at the weekend suspended flights to and from Mexico, the epicentre of the outbreak, leaving tourists at both ends stranded.

Amid frosty ties with Mexico over Beijing's handling of its nationals, a chartered AeroMexico flight was to collect 43 Mexicans quarantined in Shanghai, before flying to the capital and then heading south later in the day.

At a Shanghai hotel, armed police supervised masked medical staff in protective clothing transferring the Mexicans into about 30 ambulances taking them to the airport, said Eastday.com, a website run by the city government.

The AeroMexico flight will also pick up 10 people in Hong Kong, a Mexican consular official in the territory told AFP , but it was not clear how many people in total it would collect.

The jet would also fly home Mexicans who had not been quarantined but who wanted to go back for various reasons.

Mexican diplomats have complained that 70 of their nationals were put in isolation in mainland China despite showing no signs of the (A)H1N1 virus.

mexico swine flu pandemic outbreak 050509 01 Some of the quarantined Mexicans had travelled to China on board the same flight that carried an infected Mexican man - Asia's first confirmed case of (A)H1N1 flu - who is now in a Hong Kong hospital.

The illness, which appears to have originated in Mexico, has spread across more than 20 countries and killed 26 in all.

In the face of criticism of its handling of the affair, China has denied targeting Mexicans with its flu measures, saying they were "not directed at Mexican citizens and are not discriminatory."

But Mexican Pedro Diaz, 28, a tourist, said "a couple of hotels refused to take me in" after seeing his passport, as his countrymen arrived at the embassy here to try to get a seat on the charter plane.

22 Canadian students quarantined

China, meanwhile, also sent a plane to Mexico to fetch 200 of its citizens stranded by the flu crisis there, China Southern Airlines said in a statement, after the two countries agreed to a repatriation deal.

Amid further discontent with how China was dealing with international visitors from countries with confirmed flu cases, Canada has asked Beijing to explain the quarantine at the weekend of 22 students.

mexico swine flu pandemic outbreak 050509 04 Foreign Minister Lawrence Cannon said they had been isolated in a hotel in northwest China. Canada has one of the highest numbers of cases of the virus.

One of the students, Martin Leroy Deslauriers, told AFP by phone from the hotel that none of the students had any symptoms and they believed they were singled out by authorities in the city of Changchun for being Canadian.

"I am sure they have their reasons but I think its mostly symbolic because we are Canadian and some people had the flu in Canada," said Deslauriers, 26, from Montreal.

None of the hotel staff wore masks and teachers from their local university were allowed to come and go freely to teach classes at the hotel, he said.

At least four US citizens are now or have been quarantined in China, a US embassy official said today.