Doping tensions in Olympic swimming erupted after American Lilly King beat tainted Russian rival Yulia Efimova and US superstar Michael Phelps demanded life bans for swimmers with a drug record.
Booing broke out in the swimming arena on Monday as Efimova -- twice convicted of doping but securing an Olympic place on a last-ditch appeal -- lined up to challenge the women's 100m breaststroke final.
King narrowly beat her then slammed her rival, stoking the controversy over revelations of Russian stated-sponsored doping.
Russia's Yulia Efimova was booed as she entered the pool area and was left in tears after being beaten by Lilly King in the 100m breaststroke final