A Ukrainian drone struck an oil pipeline near the key Russian Baltic port of Primorsk early Sunday, prompting Moscow to acknowledge an oil spill while insisting there was no damage.

Ukraine confirmed it staged the latest strike on the port, near the border with Finland, that plays an important role in Russia's oil exports.

Russian air defenses shot down 19 drones in the Leningrad region and debris from one "damaged a section of the oil pipeline near the port of Primorsk, and the pipeline is being safely burned out," regional Gov. Alexander Drozdenko initially said on Telegram.

But two hours later, he wrote: "According to updated information, the oil pipeline in the area of the port of Primorsk was not damaged."

"The fuel leak occurred due to a shrapnel hit on one of the fuel tanks. The consequences have already been dealt with," he added. No casualties were reported.

Ukraine's drone forces commander Robert Brovdi said that the country's "unmanned systems forces once again struck the Transneft Primorsk port and paid a gracious visit to Lukoil in Kstovo," referring to a refinery of Russia's second-biggest oil firm in another region.

Kyiv has stepped up attacks on Russian energy infrastructure in recent weeks in a bid to reduce Moscow's earnings from oil exports, as the Middle East war pushes up prices.

Primosk, owned by the state pipeline monopoly, Transneft, is a key Russian oil exporting port, capable of handling up to 1 million barrels per day, analysts say.

The port, which was attacked a few times in March, is between the Finnish border and St. Petersburg, Russia's second-biggest city, but hundreds of kilometers (miles) from the front line in the Russia-Ukraine conflict.