RYAZAN, Russia — A massive overnight Ukrainian drone offensive has struck the western Russian city of Ryazan, killing four people, setting a major oil refinery ablaze, and leaving parts of the city covered in what terrified residents described as a sticky "oil rain".

The attack, which occurred during the night of May 15, 2026, marks one of the largest coordinated Ukrainian aerial bombardments on Russian territory this year and is the first strike on the Ryazan refinery to result in civilian fatalities.

According to Russia’s Defense Ministry, its air defense systems intercepted a staggering 355 Ukrainian drones nationwide over a single night. Ryazan regional governor Pavel Malkov confirmed that 99 of those drones targeted his region alone.

The assault appeared to be a swift and direct response to a devastating Russian missile and drone strike on Kyiv less than 24 hours prior, which claimed the lives of at least 24 people. Following that attack, Ukrainian President Volodymyr Zelensky explicitly instructed his military and special forces to organize a forceful retaliatory campaign.

The primary focus of the Ukrainian operation was the Rosneft-operated Ryazan Oil Refinery, located roughly 185 kilometers (115 miles) southeast of Moscow. As one of Russia’s premier energy nodes, the facility processes roughly 17 million tons of crude oil per year and serves as a major fuel supply line for Russian occupation forces in Ukraine.

Local accounts describe the attack as deafeningly loud, with over a hundred explosions shaking nearby neighborhoods. Several drones breached defenses to make direct hits on the industrial site, triggering a catastrophic inferno. NASA satellite imagery tracked a massive plume of thick, toxic black smoke billowing into the sky, extending more than 100 kilometers (60 miles) into the neighboring Tambov region.

As the massive fires raged, the atmospheric turbulence and heavy smoke created a bizarre and hazardous phenomenon across the city. Panicked residents took to social media to share photos and videos of a literal "oil rain" showering down, coating streets, building facades, windows, and parked cars in sticky black spots.

While the majority of the drones targeted the refinery, debris from interceptions and stray drones crashed directly into residential areas. Governor Malkov reported that two multi-story apartment buildings were badly damaged, with videos capturing a residential high-rise engulfed in smoke and flames.

The bombardment left four people dead, including a child. Dozens of other residents were wounded, with local health authorities placing the injured count at up to 28 people. In response to the damage and the toxic air quality drifting from the burning refinery, regional authorities ordered all schools and kindergartens in the affected areas to shut down immediately.

The General Staff of the Armed Forces of Ukraine formally confirmed the success of the operation, noting that the Ryazan blitz was part of a larger, highly coordinated offensive targeting Moscow’s war-funding energy revenues. Ukrainian officials stated that alongside the refinery, separate long-range strikes simultaneously targeted and hit Russian warships at the Kaspiysk naval base, as well as multiple ammunition depots, radar stations, and logistics hubs in occupied territories.

As Russian emergency teams struggle to control the blaze at the refinery, the attack underscores Ukraine's rapidly advancing capabilities to penetrate deep into Russian borders, bringing the consequences of the war directly to Russia's industrial heartland.