Russia and Ukraine escalated their battle over the Black Sea Wednesday, with a Russian strike killing three people in the Ukrainian port city of Odesa and Kyiv's drones targeting Russian shipping.

Odesa ⁠region Gov. Oleh Kiper said 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.

Three people were killed and at least three more injured after a Russian missile strike on a seven-storey residential building in Odesa, Ukrainian authorities said.

Russia in recent days has stepped up attacks on Ukraine's deepwater 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.

Ukraine, on the other hand, has expanded its campaign to disrupt logistics for Russia's forces ⁠in ⁠areas Moscow occupies in southern Ukraine and to isolate Crimea, which Russia annexed in 2014.

Ukrainian drones hit 20 Russian vessels in the Black Sea overnight, Kyiv's top drone forces commander said Wednesday.

"Now Black Sea," Robert Brovdi, the commander of Ukraine's Unmanned Systems Forces said on Telegram, adding that 116 vessels have been struck in the Sea of Azov this month.

Strikes disrupt Azov shipping

Ukrainian attacks have forced Russia, the world's top grain exporter, to restrict shipping in the Sea ⁠of Azov – a route that handles about a quarter of its grain exports, sources told Reuters. Shipping remained restricted Tuesday, they said.

Russia's Defense Ministry said Wednesday that Moscow's forces continued overnight strikes on ​Ukrainian ports it said were handling cargoes for the Ukrainian military.

It said several ​targets in the ports of Odesa and nearby Chornomorsk port had been hit, as well as four vessels it said were delivering cargoes for Ukraine's forces ⁠in the ‌ports of Chornomorsk ‌and Dnipro-Buh.

Kiper said Tuesday that two people were ⁠killed in an evening drone attack on port infrastructure ‌in the region. A civilian vessel under a Marshall Islands flag had been damaged in the attack, he ​said.

Ukraine's top grain exporter Kernel ⁠halted operations at Chornomorsk port after Russian attacks, while another Russian strike ⁠damaged its vegetable oil terminal in the Odesa region, it said late Tuesday.

Russian ⁠Foreign Minister Sergei Lavrov ​described the attacks on shipping in the Sea of Azov as "terrorism" while Russia's agriculture ministry acknowledged that exports may get diverted to other routes.