"INTENSE STRIKES"
Popko said it was the third day of attempted strikes on Kyiv in May.
"Our city has not experienced such intensity of strikes since the beginning of this year," he said, adding that debris from the downed drones had fallen on different parts of the city but there were no casualties.
Russia on Thursday said a drone attack in the southern Krasnodar region's Ilsky settlement sparked a blaze at an oil refinery.
Krasnodar Governor Veniamin Kondratyev said the refinery fire had been localised to a 400-square-metre area and was quickly extinguished by emergency services.
Shortly afterwards the governor of Russia's Rostov region, which also borders Ukraine, said a drone had hit a local refinery near the village of Kiselevka and caused an explosion and a fire.
A similar blaze Wednesday at an oil reservoir in the nearby village of Volna engulfed 1,200 square metres, with officials also blaming a drone crash.
That same day, Moscow said it shot down two drones aimed at Putin's residence and accused Ukraine of attempting a "terrorist act", with the Kremlin threatening a tough response.
Ukraine has denied any involvement and the country's Western allies have also cast doubt on the report.
"We do not attack Putin or Moscow," Zelenskyy said on a visit to Finland. "We defend our villages and cities."
On Wednesday, Kyiv said Russian strikes had killed 21 people in the southern region of Kherson, including at a supermarket and a train station.
The spate of apparent sabotage attacks has been used to underscore Russia's exposure to enemy blows as the Kremlin gears up for important anniversary celebrations.
The May 9 victory celebrations that commemorate the Soviet defeat of Nazi Germany in World War II have become a central event during Putin's rule.
Kyiv suggested that Moscow "staged" the attack, which came ahead of a widely expected Ukrainian spring counter-offensive. The US said the Russian report should be taken with a "shaker of salt".