Prosecutors on Monday raided four major domestic refiners over allegations of oil price fixing amid rising gas prices sparked by the Middle East conflict, legal sources said. The Seoul Central District Prosecutors Office sent investigators to the offices of the refiners — SK Energy Co., GS Caltex Corp., S-Oil Corp. and HD Hyundai Oilbank Co. — as well as the Korea Petroleum Association. The refiners are suspected of colluding to raise or freeze prices of oil and petroleum-related products in the domestic market. Prosecutors are reportedly looking into instances of steep oil price fluctuations before and after the outbreak of the current Mideast war. President Lee Jae Myung earlier called for clamping down on possible illegal activities by refiners and gas stations, such as price collusion, amid concerns of a fuel price spike. Korea is currently enforcing a fuel price cap system to help ease concerns over rising energy prices due to the U.S.-Israeli war against Iran.