Sheets of the stamps are selling for up to $200 on eBay

Anti-racism campaigners and White House officials had condemned the stamps, based on the Memin Pinguin cartoon, as the character has large eyes and lips.

Mr Fox said he did not understand the hostile reaction in the US, and urged Americans to read the original comics.

Many Mexicans appeared to back Mr Fox, queuing for hours to buy the stamps.

In an interview with the Associated Press news agency, Mr Fox said the Memin Pinguin character is "an image in a comic I have known since infancy".

"It is cherished here in Mexico," the president added.

He urged Americans to read the comics before rushing to judgement.

Mr Fox provoked another row in May, when he complained that Mexicans in the US were forced into taking jobs that "even blacks" don't want.

'Brothers'

In Mexico City, hundreds flocked to post offices to try and get their own copies of the stamps.

Mr Fox urged Americans to read the Memin Pinguin comics

Many took exception to comments by White House spokesman Scott McClellan that the stamps "have no place in today's world".

"We are not racists. We are not offending anyone. He is a very sweet character," shopper Teresa Montalvo said.

"People's colour is all the same to us, we are all brothers."

Businessman Cesar Alonso Alvarado accused the US of discriminating against Mexico, a country without a significant black community and little understanding of political correctness.

"They're the racists. They're worse than we are, but they just want to belittle us, like always," he said.

But there was criticism of the Mr Fox in Mexico's newspapers