MOSCOW — Ukrainian drones hit energy and military sites in St Petersburg early Wednesday hours before international guests gathered for the city’s flagship economic forum, in a blow to Russian President Vladimir Putin.Moscow downed hundreds of drones over its territory late Tuesday and early Wednesday, regional officials said, after Kyiv launched a major attack reaching as far as the Russian capital.Russian air defenses intercepted and destroyed more than 350 Ukrainian drones over areas both close to the border and deeper into the country including Moscow, St. Petersburg, and the western city of Novgorod, according to the Russian Ministry of Defense.At least 60 of the drones were downed over the Leningrad region northwest of Moscow, according to the regional governor Alexander Drozdenko.Drones were downed over Belgorod, Kursk and other western regions, as well as near Moscow and over the Sea of Azov, Russian officials added.The overnight strikes saw Pulkovo airport temporarily restrict flights, according to Russian aviation watchdog Rosaviatsia.Several long-range drones crashed into oil storage facilities after Russian air defenses tried unsuccessfully to shoot them down. There were loud explosions and black smoke rose high above the city from the blazing oil terminal, according to the Guardian newspaper.The St Petersburg’s governor, Alexander Beglov, said the Kirovsky and Krasnoselsky districts were targeted. Ukraine also struck the Kronstadt naval base and shipyard in Leningrad oblast, the port home to Russia’s Baltic fleet. Vessels were reportedly damaged.The strikes will be deeply embarrassing for the Kremlin, taking place about 15km from the forum, where Putin is due to make a keynote speech on Friday. Guests arrived for Wednesday’s opening ceremony under a pall of thick smoke. Others were unable to fly in after St Petersburg’s airport was temporarily closed.Volodymyr Zelensky, writing on social media, said the strike was the latest example of Ukraine’s “long-range sanctions”."Important facilities on Russian territory were hit last night," Zelensky wrote on X, sharing a video of black smoke rising above St Petersburg.He said drones had hit the Petersburg oil terminal, the Kronstadt base and a factory producing weapons in the Tambov region.Zelensky noted that the oil trans-shipment facility, one of the largest on Russia’s Baltic sea coast, was about 1,100km (680 miles) from Ukraine’s state border. “I thank our warriors for their precision. Ukraine’s plan for long-range sanctions is being implemented exactly as needed to bring peace closer,” he said.Gleeful Ukrainian officials shared footage of the attacks, which showed drones buzzing noisily above St Petersburg’s skyline. “The Petersburg forum is opening with a nice plume of black smoke in the background after Ukrainian strikes,” posted Serhiy Sternenko, an adviser to the Ukrainian defence minister.About 20,000 visitors from 130 countries are expected to attend the three-day annual summit, which has been described as Russia’s answer to Davos. They include the former German chancellor Gerhard Schröder, the far-right American influencer Candace Owens and the Tate brothers.Kyiv has intensified attacks hitting key Russian oil assets over the past few months, firing hundreds of long-range drones, squeezing fuel supplies and compounding economic strains for residents. In May, Ukrainian forces carried out their largest assault on the Russian capital in more than a year, state media reported at the time.