At least three people have been killed and three others wounded in Russian strikes on Odesa, the city’s military administrator says.

Several people have been killed in Russian attacks on port infrastructure in Odesa and Mykolaiv, and Ukraine said it launched drone strikes on 20 Russian vessels as the warring sides escalated their battle over the Black Sea and key trade routes.

Odesa region Governor Oleh Kiper said on Wednesday that a “massive” Russian drone and missile attack on the southern region continued for a fifth day, with civilian, industrial and port infrastructure coming under attack.

At least three people were killed and three others wounded in the Russian strikes on Odesa, the city’s military administrator Serhiy Lysak said on Wednesday.

Russia’s Ministry of Defence confirmed the strikes on the Odesa and Chernomorsk ports, saying Russian forces targeted infrastructure facilities that it claims are used to store fuel and assemble drones.

Russia in recent days has stepped up attacks on Ukraine’s Black Sea ports in the Greater Odesa area, which handle much of the country’s grain and other cargo and are vital to its wartime economy.

Meanwhile, Ukraine has escalated its campaign to disrupt logistics for Russia’s forces in areas Moscow occupies in southern Ukraine and to isolate Crimea, which Russia has occupied since 2014.

Kyiv’s drone force commander Robert Brovdi said Ukraine hit 17 Russian oil tankers, two gas tankers and one tugboat in the Black Sea.

He claimed earlier this week that 116 Russian vessels had been “hunted down” over a nine-day period.

Moscow said on Tuesday that it was preparing to redirect exports following waves of attacks on Russian shipping in the Sea of Azov, while Foreign Minister Sergey Lavrov called the Ukrainian attacks on shipping “terrorism”.

The attacks come as European Commission President Ursula von der Leyen arrived in Kyiv and said she would announce steps to deepen Ukraine-European Union defence integration.

“I will announce new initiatives to integrate our defence industries. So we can produce more, and faster,” she wrote on X, posting footage of her arrival in the Ukrainian capital.