Renault's Fernando Alonso condemned racist supporters on Friday after hate messages were posted on a Spanish website targeting Formula One title favourite Lewis Hamilton.
"If it's true, obviously this is not possible [acceptable ]," the Spaniard told reporters at the Brazilian Grand Prix.
"In 2008 we cannot have these kind of people in our world. It's not only Formula One, not only sport, it's normal life as well."
McLaren's Hamilton, the sport's first black driver, is poised to become the youngest Formula One champion at the age of 23 in Sunday's season-ending race.
The Briton, now in his second season, became a target in Spain last year after falling out with double world champion Alonso when they were team mates.
Hamilton was subjected to racial abuse from spectators at a test in Barcelona in February after which Formula One's governing International Automobile Federation (FIA) launched an anti-racism campaign.
RACIAL ABUSE
The latest controversy erupted on Thursday after British media reports about racial abuse posted on the Spanish website www.pinchalaruedadehamilton.com (translated as "burst Hamilton's tyre").
The website, first set up in 2007 when Alonso and Hamilton were fighting for the title at McLaren, appeared to have been taken down on Friday.
The FIA issued a statement condemning the "abusive and hateful comments" and team bosses added their voices on Friday.
"It's completely disgraceful," said Renault team boss Flavio Briatore.
"It's not a problem of Lewis, it's a problem of the world," said Ferrari's Stefano Domenicali.
McLaren boss Ron Dennis said Hamilton and the team would not be distracted.
"I'm aware of the site's existence although I haven't looked at any of the material," said Dennis after free practice at Interlagos.
"You just have to rise above it. If it is in any way, shape or form designed to disrupt the team or Lewis, it's not going to do it."