Rugby cannot afford to be complacent about racism in the wake of the abuse suffered by England's black soccer players in their Euro 2020 qualifier in Bulgaria, lock Maro Itoje has said.
England beat Bulgaria 6-0 in Sofia on Monday in a match marred by a section of home supporters taunting the visitors with Nazi salutes and monkey chants.
Bulgaria FA President Borislav Mihaylov resigned in the wake of the match and police in the country have detained six people so far, with more arrests likely.
Itoje told reporters in Japan on Wednesday that although such incidents were rare in rugby, the sport's authorities should not assume that would always be the case.
"It's important never to just assume that this is a free zone from any form of discrimination. I think rugby is probably ... right up there in terms of integrity, respect and how they treat people," he said.
"But I think it's important to never just assume that it's always going to be that way."
The 24-year-old said he was aware of fellow professionals and players at grassroots level being subjected to racist abuse.
Itoje called on athletes who have been subjected to racist abuse to speak out and said there should be stricter punishment for offenders.
"It's a shame because (soccer) is such a beautiful game and it's being tarred by people with racist thoughts and racist minds," he said. "It's terrible that players have to experience that when they just want to go out and play the game they love.
"Associations and teams need to take a tougher stand. Punishment needs to be more severe because it is not acting as a deterrent, especially when they go abroad to places like Bulgaria."
England play Australia in the quarter-finals of the Rugby World Cup on Saturday.