As Ukrainian forces fight to isolate a large group of Russian soldiers caught between a river in Russia’s Kursk Province and the Ukrainian border, Kyiv has launched a series of strikes at airfields, ports and oil depots in Russia aimed at degrading the Kremlin’s war effort.

A Ukrainian missile strike on the Russian port of Kavkaz hit a large cargo ferry laden with fuel on Thursday, triggering a towering blaze at the facility, according to Russian and Ukrainian officials as well as video posted to social media channels. Kavkaz is one of the country’s largest passenger ports and the main ferry terminal connecting Russia with Crimea.

“This ferry is one of the key links in the Russian military logistics chain, primarily for supplying the occupying forces with fuel and lubricants, but it also transported weapons,” a Ukrainian Navy spokesman, Dmytro Pletenchuk, said in a statement.

The attack on the transit hubs came after strikes on the only bridge linking Crimea to Russia over the Kerch Strait left it damaged, forcing Moscow to increasingly rely on large ferries capable of carrying rail cars to support its occupation forces on the peninsula, which it annexed in 2014.

“The ferry sank, effectively blocking the operation of this part of the port,” Mr. Pletenchuk said. “They still have one platform left for loading rail cars onto ferries. However, there are no ferries available.”

The RIA state news agency of Russia, citing emergency services, said a fire sparked by the attack had “practically” not affected the port’s infrastructure, but that the ferry struck by Ukraine was half submerged. It was not possible to independently assess the extent of the damage.