Ukrainian drones hit an oil terminal in St. Petersburg and set it on fire, Ukrainian President Volodymyr Zelenskyy said Wednesday. The Russian city had a yearly international economic forum promoted by President Vladimir Putin.

The drones flew more than 1,000 kilometers (600 miles) to hit the terminal, Zelenskyy said on social media. Black smoke rose over the city’s port after the attack.

Russian authorities said only that the Ukrainian drone strike hit the city’s infrastructure. They did not give more details. The airport of St. Petersburg stopped flights for a short time at night because of the attack. Authorities also stopped mobile internet services.

Putin will speak on Friday at the forum in St. Petersburg. The Kremlin thinks it is very important. Many Western investors and officials have not gone since Russia invaded Ukraine more than four years ago. Saudi Arabia is a special guest country this year and will send many business people.

The attacks are bad for Putin. Weeks later, he had to make the Victory Day parade in Moscow smaller because he was afraid of drone attacks from Ukraine.

The attacks came one day after Russian forces started a very big drone and missile attack on Kyiv and other Ukrainian cities. At least 22 civilians died and 138 were hurt. Moscow did what it said and made its regular attacks bigger.

The front line changes little because many drones make it hard to move. Both sides have tried more long-range strikes. The war after Russia invaded its neighbor is now in its fifth year, and there is no end in sight.

Ukraine attacks Russia’s oil and weapon production. This oil gives Moscow money.

Ukraine has attacked oil places many times at the port of St. Petersburg and nearby ports.

Ukrainian drone attacks at night also hit the Kronstadt naval base, an old base for Russia’s Baltic Fleet, and a factory that makes weapons in Russia’s Tambov region, 600 kilometers (370 miles) from Ukraine, Zelenskyy said.

Russia's Defense Ministry said air defenses stopped 354 Ukrainian drones overnight.

In the part of Ukraine’s Donetsk region controlled by Russia, a Ukrainian attack hit a bus going from Moscow to Crimea. Seven people died and 11 were hurt, said Denis Pushilin, the Kremlin-appointed head of Donetsk.

In the Smolensk region, two firefighters died in a Ukrainian drone attack, said the regional governor, Vasily Anokhin. He said two other firefighters and a local person were hurt.

Russia fired 198 drones at Ukraine last night. Ukraine’s air force said this. Air defenses stopped 189.

Officials in Ukraine's north Sumy region said that in the last 24 hours, one person died and 15 more people were hurt, including three children, by Russian attacks.

In southern Kherson, Russian attacks at night killed an 86-year-old woman and hurt five other people, regional authorities said.