Russian crude oil production dropped around 5% year-on-year last month to 8.7 million barrels per day, 10% below May's target, due to Ukrainian strikes on its energy infrastructure, the International Energy Agency (IEA) said on Wednesday. Seeking to hit a major source of Russia's war funds, Ukraine's attacks on refineries ‌have doubled ⁠since ⁠the start of 2026, leading to full or partial shutdowns of oil processing, according to official data, social media, and Reuters calculations.Also read| Ukraine secures fresh air defence commitments at G7 Summit in France"Due to continued strikes on oil ​infrastructure, we have cut the Russian crude forecast this year by 200,000 bpd to 8.95 million bpd," the Paris-based IEA said ​in a monthly report, noting that Ukraine ⁠had started to ‌target more remote production areas with longer-range drones. Russia ​this ​month acknowledged for the first time that oil output ⁠was down this year, blaming unplanned maintenance. The world's ​third-largest oil producer stopped publishing data on oil ​production in April 2023, just over a year after the start of its war with Ukraine.The IEA said Russian crude and oil product exports remained stable at around 7.4 million bpd in May, little-changed year-on-year despite the attacks.Total oil export revenue ‌dropped $710 million month-on-month to $20.8 billion in May, as prices eased, but this was 65% higher than a year ​ago and ​near all-time highs, ⁠it said.Also read| G7 leaders applaud Iran, Ukraine progress ahead of tackling AIThe IEA said the attacks had forced Moscow to prioritise oil products supply to the domestic market and maximise crude oil exports, ​which rose by 490,000 bpd year-on-year to 5.2 million bpd, returning to 2022 levels. Russia is set to reduce its crude oil exports as it plans to boost refinery runs in June amid looming fuel shortages, market sources said earlier this month.