** South Korean oil refiner stocks erase early gains to turn lower on govt plan to cap fuel prices
** President Lee Jae Myung says authorities will cap domestic fuel prices for first time in nearly 30 years
** S-Oil 010950.KS falls more than 1% and SK Innovation 096770.KS drops 5%, erasing early gains of 6% and 3%, respectively
** They started the session sharply higher on surging oil prices, being rare gainers amid broader market drop
** Benchmark KOSPI .KS11 falls 7.8%, as of 0413 GMT, after triggering circuit breakers earlier
** S-Oil shares still up 17% so far this month, SK Innovation down 7%, versus KOSPI's 17% loss
(Reporting by Jihoon Lee)
((jihoon.lee@thomsonreuters.com))