US energy stocks slip as Iran peace talks weigh on crude

** S&P 500 energy index .SPNY down 2.1%, tracking lower crude prices O/R

** Brent crude futures down 6.2% at $106.45/barrel, while US West Texas Intermediate crude falls 6.5% to $97.40/barrel

** Prices decline as talks between Iranian and Qatari officials raise hopes of easing Middle East supply disruptions, while Iran's president says the supreme leader has granted the government certain powers to pursue peace negotiations

** Energy majors: ExxonMobil XOM.N and Chevron CVX.N down 2.4% and 2%, respectively

** Valero Energy VLO.N, Occidental Petroleum OXY.N, Devon Energy DVN.N down between 3.1% and 3.9%; among the top percentage losers on the energy index

** ConocoPhillips COP.N down 2%, EOG Resources EOG.N falls 2.3% and Targa Resources TRGP.N down 2.6%

** Oilfield services companies Halliburton HAL.N down 2.5% and SLB SLB.N falls 2.3%

** Refiners: Phillips 66 PSX.N, Marathon Petroleum MPC.N decline 2.2% and 2.6%, respectively