Ukraine Intensifies Attacks on Russia in Crimea and Black Sea

Ukraine is stepping up its long-distance attacks into Russian-occupied Crimea and the Black Sea, launching several new strikes on Thursday, in a campaign to break down the Kremlin’s war effort by hitting targets far behind the front lines where soldiers are fighting and dying.

The Ukrainian military said it had hit a Russian surface-to-air missile defense system in Crimea and two Russian vessels at sea, a day after it struck two Russian warships docked in Crimea. The statements could not immediately be confirmed or refuted; the Russian Defense Ministry said only that attacks on a ship in the Black Sea had failed.

In recent weeks, Ukraine has sharply accelerated the pace of strikes in and around the Crimean Peninsula, a critical hub for the Russian military where it stockpiles troops, fuel, ammunition and other supplies and funnels them to the battlefields in southern Ukraine. The peninsula also contains the primary base, at Sevastopol, of the Russian Black Sea Fleet that is blockading Ukrainian ports.

The fight to reverse the Russian invasion stretches across multiple regions and hundreds of miles, but the Ukrainian military has long maintained that it cannot be won without taking aim at Russian assets and operations in Crimea. And since Moscow ended a grain-shipping agreement in July, Ukraine has been trying to establish a somewhat safe corridor for civilian freighters, in part by degrading the Russian fleet and forcing it to keep a wary distance.

“The way to victory on the battlefield is to defeat the logistics of the Russians,” Andriy Yermak, a senior adviser to the Ukrainian president, Volodymyr Zelensky, said in a statement after the Crimea strikes on Wednesday. Defeating Russia, he said, depends on not giving Moscow “the opportunity to preserve the military potential for waging an aggressive war.”

On another front, the United States on Thursday announced economic sanctions against about 170 individuals and companies, most of them Russian, whom it described as contributing to the Kremlin’s war effort through industry, finance, technology or energy, adding to the thousands already under sanctions.

Russia announced the expulsion of two American diplomats, in connection with the arrest of a Russian accused of passing information to them about the Russian war effort.

Ukraine’s three-month-old counteroffensive has made only grueling, slow-moving progress at the expense of casualties and equipment.

But Ben Barry, a senior fellow for land war studies at the International Institute for Strategic Studies, a British think tank, wrote on Thursday that Ukraine’s “deep battle” against targets far behind enemy lines “has shown signs of success in disrupting both Russian military operations” that “may set Ukraine’s forces up for breakout success or at least to significantly diminish Russia’s combat power.”

Ukraine’s military said on Thursday that it had hit an S-400 Triumf surface-to-air missile battery, one of Russia’s most sophisticated air defense systems, near Yevpatoriya, in western Crimea. The Russian Defense Ministry did not comment on the claim.

The attack featured both aerial drones and missiles, according to a Ukrainian security official who spoke on the condition of anonymity to discuss operational details. First the drones disabled Russian radar antennas, the official said, so they would not detect what came next: Neptune missiles that hit the S-400 battery.

“The air defense system of the occupiers on the land of our Crimea was destroyed,” Mr. Zelensky wrote on the Telegram app.

Local residents posted a series of unverified videos on social media showing explosions, but satellite imagery of the site was not immediately available.

Natalia Humeniuk, a spokeswoman for the Ukrainian southern command, said that there was “a concentration of military facilities” and “the presence of an airfield” in the area where the strikes took place. The explosions across Crimea, she added, are “flourishing” and will continue.

Russia’s Defense Ministry said on Thursday that one of its patrol ships, the Sergey Kotov, which has taken part in enforcing the Black Sea blockade, was targeted by five maritime drones before dawn, but they were thwarted. The Ukrainian military then claimed that its drones had hit two Russian ships. None of the statements could immediately be verified.

On Wednesday, Russian officials acknowledged that two warships in dry dock at Sevastopol had been damaged in a Ukrainian attack that apparently used cruise missiles. Russian pro-war military bloggers and a Russian news outlet identified the vessels as a Kilo-class attack submarine and a Ropucha-class landing ship, and satellite images appeared to confirm that they were a submarine and a landing ship.

As Russia seeks more secure ways to support its forces in Ukraine, large landing ships are an important logistical asset, and the ship, depending on the extent of the damage, would be the second one taken out of commission by a Ukrainian strike in recent weeks.

On Monday, Ukrainian special forces said they had reclaimed several oil and gas platforms in the Black Sea that the Russians had seized. Ukraine’s claim could not be independently verified, and the Russian Ministry of Defense did not comment.

Military analysts and the British military intelligence agency say Russia had installed radar installations and long-range missile systems on such platforms, which were used to attack Ukraine and defend against strikes on Russian installations in Crimea. Ukrainian military officials said one objective of the operation was to impair the Russians’ ability to detect threats aimed at Crimea.

In 2014, President Vladimir V. Putin of Russia sent troops into Crimea, a part of Ukraine, and illegally annexed it. The same year, he fomented and backed a separatist war by pro-Russian forces who took control of part of the Donbas region of easternmost Ukraine, bordering Russia.

The Kremlin used both regions as jumping-off points for Moscow’s full-scale invasion nearly 19 months ago, but Crimea’s geography makes the Russian positions there more vulnerable.

From Crimea to the regions in southern Ukraine with the most intense fighting, there are just three highways and two railroads. There is just one rail and road bridge from Russia to Crimea, across the Kerch Strait. Around Crimea, Russian logistics rely heavily on a handful of hubs.

Ukrainian forces have repeatedly fired missiles and drones at the Russian military depots there and at all the arteries linking Crimea to both southern Ukraine and Russia, trying to turn the peninsula into an island.