United States' Lilly King competes in a semifinal of the women's 100-meter breaststroke during the swimming competitions at the 2016 Summer Olympics, Sunday, Aug. 7, 2016, in Rio de Janeiro, Brazil. (AP Photo/Lee Jin-man)
Olympic organizers are urging competitors to take the trash talk out of the Summer Games.
It came after Efimova waved a No. 1 finger after her semifinal in the 100-meter breaststroke.
United States' Lilly King, center, competes in a semifinal of the women's 100-meter breaststroke during the swimming competitions at the 2016 Summer Olympics, Sunday, Aug. 7, 2016, in Rio de Janeiro, Brazil. (AP Photo/David J. Phillip)
Efimova is being allowed to compete in Rio after a 16-month suspension was placed on hold while world anti-doping officials conduct further studies on the drug.
International Olympic Committee spokesman Mark Adams says "people should be free to compete in tranquility and not be addressed by others. We would encourage people to respect their fellow competitors."
A smattering of boos greeted Efimova after she won her preliminary heat.
At an IOC briefing, Adams said: "Brazilian fans seem to be pretty egalitarian. They seem to boo athletes from many countries. It's quite difficult to work out why they might be booing one athlete and not another."
As for King, she seems pretty confident, regardless of who is with her in the pool.