KYIV, Ukraine — As Ukrainian forces launched a renewed assault on Snake Island south of Odesa in the Black Sea, recent strikes by Ukrainian forces suggested that powerful Western anti-ship weapons were arriving in Ukraine and threatening to undermine Russian naval domination.
The Ukrainian military southern command said late Tuesday that it was engaged in battle using “various forces and methods of destruction” to attack Russian infrastructure on the island, a speck of land that is critical to efforts to control the Black Sea, but it declined to provide details.
At the same time, Ukrainian officials defended the targeting of Russian drilling infrastructure in the Black Sea, saying Moscow was converting its drilling platforms to military installations by installing high-tech surveillance and communications systems on the rigs.
A Russian official said on Monday that Ukraine had hit three natural-gas rigs belonging to the breakaway Crimean arm of Ukraine’s national gas company. Ukraine’s government did not confirm the strike or its exact target, but satellite images from NASA’s Worldview system used to detect fires showed what appeared to be a burning drilling rig off the coast of Crimea.
Andriy Zagorodnyuk, the former Ukrainian defense minister, said that Ukrainian weapons hit a former natural-gas rig on Monday where Russian forces had placed radio-jamming equipment, blocking Ukraine from getting an accurate picture of the area.
Mr. Zagorodnyuk said the strikes may be an indication that important naval weapons Ukraine has been seeking from its Western allies had finally arrived. Ukrainian officials have been cautious in making information about the weapons used in attacks off the public coast, saying that specifics could help the Russians.
The Russians use some rigs “solely as military installations,” said Mr. Zagorodnyuk, who leads the Center for Defense Strategies, a Ukrainian security think tank. They install electronic warfare equipment for jamming and radar equipment and add short-range missiles for attacking ships and other objects, he said.
Russia appeared to respond to the attack on its infrastructure with nine missiles fired at Odessa overnight Monday. Moscow also appears to be stepping up its missile attacks on Ukrainian coastal defense systems around the south, with the Ukrainian military reporting more than two dozen cruise missile attacks in recent days.
Serhii Bratchuk, the spokesman for the Odessa regional military administration, said Russia’s missile barrage on Odessa included one that struck a food warehouse and another that hit a cemetery.
The fighting on the Black Sea comes as the world wrestles with a global food crisis caused by a Russian naval blockade that is keeping Ukrainian ships from leaving port with millions of tons of grain.
Snake Island — which covers just 46 acres of rocks and grass — is vital to both the Ukrainians and the Russians. If the Russians have control of the island 180 miles off the coast of Odesa they can control shipping lanes in the northwest corner of the Black Sea.
After a series of attacks in May by Ukrainian forces in and around Snake Island, Russia has reinforced its outpost there with multiple surface-to-air rocket systems, according to satellite imagery and Ukrainian officials.
Mr. Bratchuk said that the Russians are trying to turn the garrison on the island into “something that could be the analogue of the warship Moskva.” The Ukrainians sank the Moskva, the flagship on the Russian Black Sea Fleet, in April. While she had a handful of Ukrainian made anti-ship missiles, called Neptunes, powerful Harpoon systems are just now arriving in the country from the West.
The current round of fighting around Snake Island appeared to kick off on June 17, when the Ukrainians struck a Russian naval tugboat as it was on a mission to deliver weapons and personnel to the island.
On Tuesday, the British military’s intelligence agency said that Ukraine “almost certainly” used newly delivered Harpoon missiles in the attack — their first demonstrated use.
Ukrainian coastal defense capabilities have now “largely neutralized” Russia’s ability to project maritime force in the northwestern Black Sea, the British analysis said.