Oil prices eased but remained near four-month highs as the impact of fresh U.S. sanctions on Russian oil remained the market's main focus, ahead of U.S. inflation data this week. Brent futures slipped 53 cents, or 0.7%, to $80.48 a barrel by 0746 GMT, while U.S. West Texas Intermediate (WTI) crude fell 44 cents, or 0.6% to $78.38 a barrel. Prices jumped 2% on Monday after the U.S. Treasury Department imposed sanctions on Gazprom Neft and Surgutneftegas as well as 183 vessels that trade oil as part of Russia's so-called shadow fleet of tankers. Headlines surrounding Russia oil sanctions have been the dominant driver for oil prices over the past week, and combined with resilient U.S. economic data, the tighter supply-demand dynamics have been seeing some momentum, said IG market strategist Yeap Jun Rong. With prices rising fast and furious by close to 10% since the start of the year, it does prompt some profit-taking as event risks around upcoming U.S. inflation data releases loom. The U.S. producer price index (PPI) will be released later in the day, with consumer price index (CPI) data on Wednesday. Any rise in core inflation greater than the forecast 0.2% on Wednesday would threaten to close the door to further Federal Reserve interest rate cuts this year. Lower interest rates typically help in stimulating economic growth, which could prop up oil demand. The recent rally to a three-month high does signal an improvement in sentiment, but while broad bearish pressures have eased for the time being, a stronger catalyst is still needed to fuel a sustained broader uptrend, IG's Yeap added. While analysts were still expecting a significant price impact on Russian oil supplies from the fresh sanctions, the physical impact could be less. These sanctions have the potential to take as much as 700k b/d of supply off the market, which would erase the surplus that we are expecting for this year, ING analysts said in a note. However, the actual reduction in flows will likely be less, as Russia and buyers find ways around these sanctions - clearly there will be more strain on non-sanctioned vessels within the shadow fleet. Demand uncertainty from major buyer China could blunt the impact of the tighter supply. China's crude oil imports fell in 2024 for the first time in two decades outside of the COVID-19 pandemic, official data showed.