Poland scrambled fighter jets and temporarily closed its airspace on Sunday after a Russian attack on Ukraine that Ukrainian President Volodymyr Zelenskyy said lasted for more than 12 hours.

Polish radar reconnaissance systems were put on the highest level of alert, Poland’s military posted on X, and NATO F-35 jets patrolled the skies until the attack ended. There were no airspace violations, the military said.

The scrambling of jets and airspace closures are becoming more frequent as multiple NATO countries report drone sightings and other incursions. NATO said on Sept. 12 that the defense alliance will send more warplanes and air defense systems to the eastern flank in response to Russian incursions into NATO airspace.

Three Russian drones were shot down in Poland’s airspace earlier this month. And Denmark reported fresh drone sightings above defense sites on Friday and Saturday, after a wave of drone activity earlier in the week temporarily shut down major Danish airports.

The Russian attack early Sunday included nearly 500 attack drones and more than 40 missiles, including the Iranian-Russian Shahed drones, Zelenskyy said. Dozens were wounded in the strikes and among the dead was a 12-year-old girl, he said.

“The massive Russian attack on Ukraine lasted for more than 12 hours,” Zelenskky said. “Brutal strikes, deliberate and targeted terror against ordinary cities,” he said.

More than 15 locations in the capital were damaged, including multi-story resident buildings, “in particular in the Solomenskyi district,” Timur Tkachenko, the head of Kyiv’s military administration, said in a post on Telegram.

The attacks came just hours after Zelenskyy warned Europe that the recent increased drone activity and airspace incursions are a sign that Russian President Vladimir Putin would not stop with Ukraine.

“Putin will not wait to finish his war in Ukraine. He will open up some other direction. Nobody knows where,” Zelenskyy said.

At the United Nations General Assembly in New York on Saturday, Russia’s Foreign Minister Sergei Lavrov said his country has no intention of attacking EU or NATO countries. But Moscow will respond with a “decisive response” to any aggression directed toward Russia, he said.