KYIV, Ukraine — Hours after accusing Ukraine of attacking its ships with a swarm of drones, Russia withdrew on Saturday from an agreement aimed at bringing down global food prices by allowing the export of grain from Ukrainian ports.
The Russian decision, which United Nations and Ukrainian officials said could exacerbate hunger, brought to a screeching halt a rare case of wartime coordination that had allowed the movement of more than 9 million tons of agricultural products, many of them bound for poor countries.
Stéphane Dujarric, a spokesman for the United Nations secretary general, António Guterres, called on the warring parties to ensure that the grain deal continued.
“It is vital that all parties refrain from any action that would imperil the Black Sea Grain Initiative, which is a critical humanitarian effort that is clearly having a positive impact on access to food for millions of people around the world,” Mr. Dujarric said.
President Volodymyr Zelensky of Ukraine called Russia’s decision “predictable,” saying in his nightly address on Saturday that Russia had been “deliberately aggravating” the food crisis since September.
“Russia is doing everything to ensure that millions of Africans, millions of residents of the Middle East and South Asia, find themselves in conditions of artificial famine or at least a severe price crisis,” he said, urging a strong international response.
“The world has the power to protect people against this,” he added.
Adrienne Watson, a spokeswoman for the U.S. National Security Council, said that by suspending the grain agreement, Russia would “again be trying to use the war it started as a pretext for weaponizing food.”
The size of Saturday’s attack and the extent of the damage it caused remained unclear.
In a statement, the Russian Foreign Ministry accused Ukraine of launching “massive air and sea strikes using drones” on its Black Sea Fleet’s ships, infrastructure and naval base in the port city of Sevastopol.
That meant, the ministry said, that Russia could no longer ensure the security of cargo ships taking grain from Ukrainian ports and so would “suspend its implementation from today for an indefinite period.”
Russian officials said earlier Saturday that 16 drones had attacked Russia’s Black Sea Fleet, damaging at least one vessel, a minesweeper, before all of the attacking aircraft were repelled. The Russian Defense Ministry accused “the Kyiv regime” of carrying out the operation, but did not initially mention any civilian vessels.
The Black Sea Fleet has released devastating volleys of ship-fired missiles across the breadth of Ukraine, carrying out some of the deadliest strikes of the war.
Ukrainian officials did not comment publicly on the attack, and have maintained a policy of official ambiguity about strikes behind the front lines.
But a senior Ukrainian official said that the minesweeper Ivan Golubtsov had been severely damaged, possibly beyond repair. A second ship, the Admiral Makarov, sustained damage to the hull that could easily be fixed, the official said.
The attack appeared to be the most recent example of Ukrainian forces striking sensitive Russian sites from afar, illustrating how homemade drones and powerful weapons provided by Western nations have given the Ukrainians abilities that only the Russians had early in the war.
Along the front lines in southern Ukraine, precision-guided rockets and artillery shells now give Ukrainian forces superior range and accuracy, commanders and military analysts say, because of weapons largely lacking in Russia’s arsenal. And Ukrainian soldiers are blowing up Russian armored vehicles worth millions of dollars with cheap homemade drones and more advanced drones and other weapons provided by the United States and other allies.
The grain deal, which was brokered by the United Nations and Turkey in July, was hailed as a diplomatic breakthrough, although its implementation remained shaky and Russian officials complained that they were not getting their due from the agreement.
The deal allowed commercial vessels carrying agricultural products to leave Ukraine and cross the Black Sea to Turkey, where their cargo would be inspected by a joint command including officials from Ukraine, Russia, Turkey and the United Nations.
As of Thursday, 9.2 million tons of grain and other foodstuffs had been exported through the deal, according to the office overseeing its implementation. On Friday, six vessels left Ukrainian ports carrying more than 220,000 tons of grain bound for Israel, Belgium, China, Italy and Egypt.
Both Ukraine and Russia are struggling to find storage for bumper crops of grain, a problem that stopping exports would exacerbate.
But Russia has struggled to export agricultural products and fertilizer as it is permitted to under the agreement because ports, insurers, banks and other businesses fear being punished for working with Russian exports, despite guarantees in the deal that they would not.
Even before Saturday’s attack, Russia had already been considering suspending the deal, Alexandra Prokopenko, a Russian policy analyst, wrote for the Carnegie Endowment for International Peace last month.
“The benefits for Moscow of signing the grain deal were always modest,” she wrote. “It’s likely that Russian President Vladimir Putin simply wanted to have an additional means of exerting pressure on the West. From his point of view, now is the time to wield that power.”
Mr. Putin has complained that grain was not being shipped to where it was supposed to go, but the original deal did not specify destinations, Ms. Prokopenko noted.
Rather, driving up grain prices would further fuel inflation in Europe, already staggering under the price of gas, and hence create pressure on Western governments, she wrote.
The drone attack on Saturday struck Sevastopol, a port on the Crimean Peninsula, which has been under Kremlin control since Moscow illegally annexed it in 2014.
The area holds immense symbolic importance for Mr. Putin. An explosion this month on the bridge linking the peninsula to Russia prompted Mr. Putin to retaliate with mass strikes across Ukraine that killed dozens of people and targeted critical infrastructure.
Ukrainian officials have continued to accuse Russian forces of harsh treatment of local populations in occupied parts of southern and eastern Ukraine.
Mr. Zelensky said that Russia was transforming the once thriving southern port city of Kherson into a wasteland, accusing the Russians of stealing ambulances, closing health care facilities and threatening doctors.
“Russia is turning the Kherson region into a zone without civilization,” he said in his nightly address to the nation on Friday. “They are dismantling the entire health care system there.”
His stark portrayal of the conditions in the city, the first major city to fall to the Russians after their invasion of the country in February, came as Ukrainian forces advanced on Kherson from multiple directions and as the proxy officials Russia had put in place to administer the area were fleeing east to territory more firmly under Russian control.
Those officials have said they “evacuated” tens of thousands of civilians, but they have provided no evidence to support those claims.
Ukrainians, on the other hand, accuse the Russians of carrying out Soviet-style forced deportations, like those that have been documented in places like Mariupol that fell under Russian control.
It is increasingly difficult to reach people in Kherson, with phone and internet services unreliable and some residents saying Russian forces have searched people’s cellphones for suspect communications.
One man, Oleksandr, 50, said in a message shared with The New York Times on Saturday that his wife had seen men at the hospital on Friday turning off the heat and packing up “all worthy medical equipment” before ordering patients to leave.
“They are closing the regional hospital in Kherson,” Oleksandr said, providing only his first name for fear of retribution. “Patients, irrespective of their condition, are sent home, even if they had surgery yesterday.”
As the fighting continues, Ukrainian officials are struggling with a different type of battle: trying to provide electricity to their people.
Dozens of aerial attacks on Oct. 10 and the days after it have destroyed 30 percent of the nation’s power stations. In the weeks since, Ukrainian electrical workers have been racing to make repairs, but it is a monumental challenge.
Mr. Zelensky said Friday that four million Ukrainians faced restrictions on power use, and that people across the country struggled with rolling power outages that he said were the only way the country’s energy provider could prevent a “complete blackout.”
In an interview, Volodymyr Kudrytskyi, the chief executive of Ukrenergo, Ukraine’s national electric utility, described a sustained campaign of drone strikes that Russian officials have said is meant to cause civilian suffering and force Ukraine to submit to the Kremlin’s will.
“Virtually every day, they hit some target run by Ukrenergo,” he said.
More than 5,500 electrical maintenance workers are struggling to make repairs as quickly as they can under harrowing conditions, Mr. Kudrytskyi said.
Dmitri A. Medvedev, a former Russian president and prime minister and the current deputy head of Russia’s Security Council, said in statement on Friday that Ukraine would regain energy stability only when it recognized Russia’s demands as legitimate.
But Mr. Zelensky remained defiant. “We are not afraid of the dark,” he said to the nation from the darkened streets of Kyiv late Thursday.
Reporting was contributed by Neil MacFarquhar from Paris, Ivan Nechepurenko from Tbilisi, Georgia, Ben Hubbard from Istanbul, Jim Tankersley from Washington and Victoria Kim from Seoul.