Ukraine has attacked a major oil terminal in Russia’s second city, St. Petersburg, and other targets in the country’s northwest.

In a social media post, President Volodymyr Zelensky wrote: “Ukraine’s defense forces attacked port oil infrastructure that generates revenue for Russia’s war.” He also said a “major military target” was hit overnight at Kronstadt, a nearby naval base.

St. Petersburg Governor Aleksandr Beglov said the city was under a “massive” drone attack and admitted the oil terminal was hit. No casualties reported.

In recent months, Ukraine has stepped up its long-range drone attacks against Russia’s critical energy infrastructure, causing fuel shortages in several regions.

In his Saturday morning post, Zelensky said the targets hit in St. Petersburg and the surrounding region were about 850 kilometers (528 miles) from the border with Ukraine.

The extent of the damage was not immediately clear, but a video released by the Ukrainian president showed a drone flying toward a target and a huge plume of black smoke billowing from the area after the attack.

The BBC later verified that the St. Petersburg oil terminal had been hit.

Ukraine’s military described the terminal as “one of the largest” in Russia, capable of producing 12.5 million tons of petroleum products a year.

The military also said a key naval base of the Russian Baltic Fleet in Kronstadt was attacked.

Russia has not commented publicly on the claim.

In a message on Telegram, Governor Beglov said that 72 Ukrainian drones were shot down over St. Petersburg and the Leningrad region.

He urged city residents to stay home until the drone threat is lifted. It warned that mobile Internet services could also be affected.

More than five million people live in Saint Petersburg.

In a separate development on Saturday, Ukraine’s military denied that the key eastern Ukrainian town of Kostyantynivka was now under full Russian control.

Military spokesman Maj Andriy Kovalyov told the BBC that “Kostyantynivka remains under the control of the Ukrainian Defense Forces.”

He admitted that there were “cases of infiltration of small infantry groups deep into the combat formations of our forces,” but added that such groups were being identified and destroyed.

His comments came a day after Russian President Vladimir Putin said Russian control over the town of Kostyantynivka had been established in June.

Putin did not provide any evidence to support his claim.

Later on Saturday, Zelensky wrote on Telegram: “If Kostyantynivka is now under Russian control, then Putin will probably have no problems meeting me there and finding diplomatic solutions to finally end the war. But still, he will not cross the front line: the truth is very different from Putin’s words.”

Kostyantynivka is one of several heavily fortified towns that make up Ukraine’s “fortress belt” in the Donetsk region, most of which is occupied by Russia.

President Putin launched a full-scale invasion of Ukraine in February 2022, and Moscow currently controls about 20% of Ukrainian territory.