At least 13 people were killed and 39 others wounded on Monday in a Ukrainian drone attack on an industrial city about 600 miles east of Moscow, according to the local mayor, signaling a further escalation of Ukraine’s campaign of airstrikes deep inside Russia.

Russian investigators said that civilian and industrial sites had been hit in the city, Nizhnekamsk, which is home to one of Russia’s largest and most advanced oil refineries. In a statement, the country’s Investigative Committee said a child was among those killed.

The strike was among the deadliest Ukrainian attacks on Russian territory since the full-scale war began in 2022, demonstrating Kyiv’s growing ability to strike far beyond the conflict’s front lines. Moscow has targeted Ukrainian cities with heavy missiles and drones throughout the invasion, regularly causing widespread civilian casualties.

In recent months, Ukraine has systematically targeted Russian oil refineries to disrupt fuel supplies to the military and to civilian consumers.

The campaign has caused rare disruptions in Russia, a major oil producer, leading to long lines at gas stations. Although the Kremlin scrambled to resolve the shortages and lines have since dissipated in major cities like Moscow and St. Petersburg, supply pressures remain.

Ukraine has also begun targeting Russia’s logistics infrastructure in recent weeks, hitting at over 20 warehouses belonging to Wildberries, the country’s largest online retailer.