(CNN) -- Athlete Paraskevi Papachristou has been expelled from Greece's Olympic team for posting an offensive comment about African immigrants on Twitter, a team spokeswoman said Wednesday.
"With so many Africans in Greece, the mosquitoes from the West Nile will at least be eating some homemade food," Papachristou said on Twitter.
The Hellenic Olympic Committee ruled Papachristou, a triple jumper, would be barred from participating in the London Olympics that begin Friday.
"She made a mistake but it was serious," the spokesman said. "It was unforgivable."
Papachristou apologized for making the remarks about African immigrants but her medal hopes were gone.
"I would like to express my heartfelt apologies for the unfortunate and tasteless joke I published on my personal Twitter account," she wrote on Facebook.
"I am very sorry and ashamed for the negative responses I triggered, since I never wanted to offend anyone, or to encroach human rights.
"My dream is connected to the Olympic Games and I could not possibly participate if I did not respect their values. Therefore, I could never believe in discrimination between human beings and races."
Papachristou's Twitter post drew public criticism and calls for her to be suspended from the Greek Olympic team.
Two of the three parties forming Greece's coalition government also issued statements on the matter.
The Democratic Left said that "this racist humor and 'jokes' that affect human lives are not tolerated by Greek society, (and) they cannot flourish in Greek athletics."
The socialist PASOK party said "matters that are to do with the human status should not be treated lightly by anyone and especially from the members of the sports community, who are symbols to young people."
Greek media reported that Papachristou has in the past posted comments about the extreme right wing Golden Dawn party.
CNN's Elinda Labropoulou contributed to this report.