** Shares of U.S. energy companies up premarket, tracking crude prices O/R

** Brent crude futures LCOc1 up 5.33% at $96.88/barrel while U.S. West Texas Intermediate crude futures Clc1 rise 4.89% to $91.52

** Oil prices rise as Iran stepped up attacks on oil and transport facilities across the Middle East, fuelling concerns of a prolonged conflict and potential disruptions to oil flows through the Strait of Hormuz

** Top oil and gas companies Exxon Mobil XOM.N and Chevron CVX.N both up 0.8%

** Shares of Murphy Oil MUR.N, SM Energy SM.N, Occidental Petroleum OXY.N and ConocoPhillips COP.N climb between 1.2% and 2.2%

** Oilfield service provider Halliburton HAL.N up 0.5%

** Refiner Marathon Petroleum MPC.N rises 1.2%

(Reporting by Varun Sahay in Bengaluru)

((Varun.sahay@thomsonreuters.com))