Refined products are the likeliest first reaction, with diesel the focus and refining margins a cleaner signal than flat crude, since a refinery outage removes product supply while trimming crude demand. The bid may fade quickly if repairs look short, but a longer outage, or a follow-up strike on other Russian refining assets, would extend it. Traders will watch how the diesel curve and margins open when trading resumes, and whether the move stays in diesel or spreads to other fuels.---Ukraine's biggest drone raid on the Moscow region has reportedly set the capital's main refinery ablaze, putting a large slice of Moscow's fuel supply, and a diesel market already on the rise, continuing in traders' sights.Summary:Moscow Mayor Sergei Sobyanin said 450 drones heading for the capital were shot down in what he called the largest attack on the region, which also hit the city's main oil refinery and a residential building.The region's governor said at least two people were killed and 20 injured.Telegram channels reported a major fire at the Moscow Oil Refinery in Kapotnya on September 19 and 20, and a large fire also appeared to have broken out at the Sofyino logistics technopark.The refinery has capacity of about 11 million tonnes a year, or roughly 220,000 barrels per day, and supplies about 40% of Moscow's fuel market and 70% of the region's demand for petrol and aviation gas.Ukrainian President Volodymyr Zelensky confirmed that Kyiv hit a key Russian oil facility and a logistics site in the region with drones and missiles, calling them assets worth billions of dollars to the war effort.Ukraine has carried out its largest drone attack on the Moscow region, hitting the city's main oil refinery and a residential building, according to Moscow Mayor Sergei Sobyanin. Sobyanin said 450 drones heading for the capital were shot down and described it as the most massive attack of its kind on the area. The region's governor said at least two people were killed and 20 injured.Telegram channels reported that photos and videos circulating overnight on September 19 and 20 showed a major fire at the Moscow Oil Refinery in the Kapotnya district, and a large fire also appeared to have broken out at the Sofyino logistics technopark. The extent of the damage to the refinery is not yet clear.The Kapotnya plant is one of Russia's largest refining facilities, with capacity of about 11 million tonnes of crude a year, or roughly 220,000 barrels per day. It supplies about 40% of Moscow's fuel market and 70% of the Moscow region's demand for petrol and aviation gas, which makes it central to domestic fuel supply in the capital.Ukrainian President Volodymyr Zelensky confirmed that Kyiv had struck a key Russian oil facility and a logistics site in the region using drones and missiles. He said the targets represented billions of dollars that help sustain Russia's war effort.For markets, the immediate question is how long any outage lasts. A refinery of this scale is primarily a refined products story, and with diesel already rallying, traders may see the strike as a reason to extend the move. That case rests on damage that has yet to be verified, and a short outage would limit the impact. The supply loss falls mainly on Moscow's domestic market, so any effect on Russian export flows would depend on how authorities respond, which is not yet known.Attention now turns to official confirmation of the damage and the expected repair time, and to whether Ukraine follows up with further strikes on Russian refining and logistics sites, which seems very likely indeed. This article was written by Eamonn Sheridan at investinglive.com.