** U.S.-listed shares of oil firms fall premarket, tracking dip in oil prices O/R
** Brent crude futures LCOc1 down 2.1% at $60.02/barrel; U.S. West Texas Intermediate crude CLc1 slips 2.28% to $56.96/barrel
** Oil prices decline as OPEC+, over the weekend, accelerated oil output hikes, raising concerns about more supply coming into a market clouded by an uncertain demand outlook
** Energy majors Chevron CVX.N and Exxon XOM.N down 1.3% each
** APA Corp APA.O falls 1.6%, Devon Energy DVN.N down 1.5%, EOG Resources EOG.N and ConocoPhillips COP.N dips 1.8% respectively
** Oilfield service companies Halliburton HAL.N and SLB SLB.N down ~2% and 1.7% respectively
** Refiners Phillips 66 PSX.N dips 1.7% and Marathon Petroleum MPC.N down 1.8%
(Reporting by Sumit Saha in Bengaluru)
((Sumit.Saha@thomsonreuters.com;))