A Ukrainian drone attack Monday on the Russian city of Nizhnekamsk killed 13 people and wounded 38 others, authorities in the Tatarstan region said.

Ukraine has targeted Russian oil facilities with long-range drones almost daily in recent months. The barrage has caused fuel shortages in Russia, eaten into Russian refining capacity, and unsettled the Russian public.

Ukrainian President Volodymyr Zelenskyy says it is a campaign to force Russian President Vladimir Putin to the negotiating table and stop his more than 4-year-old invasion.

Nizhnekamsk came under a “massive” drone attack targeting industrial and civilian facilities on Monday morning, according to the press service of Tatarstan’s head, Rustam Minnikhanov. No further details were immediately available.

Ukrainian officials made no immediate comment.

Nizhnekamsk is roughly 750 miles east of the Ukrainian border and has a population of about 240,000. The city is an important oil refining hub, home to two refineries and a petrochemical plant.

Ukraine’s domestically developed long-range drones have flown increasing distances deep inside Russia, with some now reaching Siberia, around 2,000 kilometers (1,200 miles) from the countries’ border.

“We do deliver entirely justified responses, and every Russian strike will be met with our response. Russia’s war will be felt more and more at their own home — in Russia,” Zelenskyy said late Sunday on social media.

“The only reason this is still continuing is Russia’s unwillingness to end this war.”

Russia has also regularly battered Ukraine from the air using missiles, powerful glide bombs and drones, hitting civilian areas and causing thousands of civilian casualties, according to the United Nations.

The World Health Organization’s European office said Monday that one of its warehouses in the central Dnipro region of Ukraine had been struck twice in less than 24 hours.

The attacks destroyed emergency supplies worth an estimated $500,000 that were intended for front-line health facilities, it said in a statement.

No casualties were reported.