A Lithuania fan admitted a "racially aggravated behaviour" charge after making Nazi gestures and monkey chants during the team's win against Nigeria on Tuesday. He was fined 2,500 British pounds ($3,910) at a London court.
Racist behaviour in the stands will not be tolerated, International Basketball Federation secretary general Patrick Baumann told reporters Saturday.
"We are absolutely against any of this and we have indicated to the Lithuanian delegation that it would be better for them if they were to communicate with their fans," to behave properly, he said.
Lithuania, which took bronze at the 2010 world championship won by the U.S., could be punished in other competitions if their fans cause further racist incidents in London.
"If it happens it is going to have other consequences beyond the London Games," Baumann said. "This is about respecting their opponents, it is about respecting the Games, the Olympic values, and it is a celebration of friendship between people from all over the world."
Olympics organizers said racist fans are being ejected from venues.
"If we see any, these people will be asked to leave, and that is what we have been doing," organizing committee spokeswoman Jackie Brock-Doyle said.
In court on Wednesday, a lawyer for the Lithuanian fan on trial said his client believed his gestures and behaviour were acceptable at sports matches at home.