Anderson Silva's middleweight title defence against Chael Sonnen has been shifted from Brazil to Las Vegas.
The UFC had hoped to stage their rematch June 23 in Havelange Stadium in Rio de Janeiro before a crowd of 80,000-plus. But president Dana White told a news conference in Brazil on Tuesday that the fight had to be shelved because of a scheduling conflicts with the June 20-22 United Nations Conference on Sustainable Development.
The fight will now take place July 7 at the MGM Grand Garden Arena.
Their first meeting was a classic and Sonnen has stirred the pot for the second.
Sonnen dominated the first four rounds of his UFC 117 bout with Silva in August 2010 before being caught in a triangle choke in the fifth round.
The 36-year-old Silva (29-4) is widely regarded as the best pound-for-pound fighter in mixed martial arts. The Brazilian is 14-0 in the UFC.
The 34-year-old Sonnen (28-11-1) is a former top U.S. amateur wrestler with a talent for trash-talking.
UFC 148 will also feature a bantamweight championship bout between title-holder Dominick Cruz and Urijah Faber, rival coaches on the current season of "The Ultimate Fighter," and a light-heavyweight matchup of former champions Tito Ortiz and Forrest Griffin.
Also on the card, Rich Franklin fights Cung Le and Michael Bisping takes on Tim Boetsch.
UFC 147 will take place in Brazil featuring a rematch of Vitor Belfort and Wanderlei Silva, currently serving as rival coaches on the "Ultimate Brazil" TV show.
Heavyweight Fabricio Werdum will meet Chicago police office Mike Russow on the Brazil card.