** S&P 500 energy index .SPNY falls 0.6% as investors assess effect of U.S. sanctions on Russia's two biggest oil companies and a potential OPEC+ plan to raise output** Brent crude futures LCOc1 were down 1.37% at $64/bbl and U.S. WTI crude futures Clc1 down 1.3% at $60.41** "The oil market is still debating whether the latest sanctions will impact Russian oil exports or not, with market players reducing somewhat the supply risk premium built in last week," said UBS analyst Giovanni Staunovo** APA APA.O falls 3.7%, most on the energy index

** Devon Energy DVN.N, Diamondback Energy FANG.O and Occidental Petroleum OXY.N down 1% to 2%

** Refiners Valero VLO.N and Marathon Petroleum MPC.N down 1%

(Reporting by Varun Sahay)

((Varun.sahay@thomsonreuters.com))