** S&P 500 energy index .SPNY up 2.4%, tracking a rise in crude prices O/R

** Brent crude oil futures LCOc1 were up 1.77% at $70.02 a barrel; U.S. West Texas Intermediate crude CLc1 rose 1.89% to $65.17/barrel

** Prices rise on investors' worries about escalating tension between Iran and the U.S., which were preparing to resume negotiations, while a weekly report showing a large build in crude inventories in the U.S. limited gains

** Energy majors Exxon Mobil XOM.N and Chevron CVX.N were up 2.8% and 1.5%, respectively

** SLB SLB.N, Williams Companies WMB.N, Baker Hughes BKR.O and EOG Resources EOG.N rose between 1.5% and 4.3% — the top gainers on the energy index

** Oilfield services companies ConocoPhillips COP.N gains 2.4%, Occidental OXY.N up 2.8% and Diamondback Energy FANG.O rises 2.9%

** Refiners Phillips 66 PSX.N up 2.2%, Marathon Petroleum MPC.N rises 2% and Delek US Holdings DK.N gains 3.1%

(Reporting by Pranav Mathur in Bengaluru)

((Pranav.Mathur@thomsonreuters.com))