As Russia’s blockade of Ukrainian ports threatens the country’s grain exports and fighting rages in the east, European officials blamed Moscow for a looming global food crisis.

Vasily Nebenzya, Russia’s UN ambassador, walked out of a Security Council meeting on Monday after European Council President Charles Michel accused the Kremlin of weaponizing food supplies in a heated exchange.

Josep Borrell, the European Union’s foreign policy chief, also questioned Russia’s claims that it is not impeding grain exports, citing reports that Moscow struck Ukraine’s second-largest grain terminal in the southern port city of Mykolaiv over the weekend.

On Sunday, Russia launched cruise missiles from the Black Sea toward Mykolaiv, according to the Ukrainian military’s southern command. According to the command, two missiles were shot down, but others hit port facilities and grain storage silos.

Mr. Putin has previously denied that Moscow is impeding Ukrainian wheat exports. He stated that it was Ukraine’s responsibility to demine Black Sea ports, and that Russia was ready to export Ukrainian wheat through ports it now controls on the adjacent Azov Sea.

Dmitry Peskov, a Kremlin spokesman, said on Tuesday that demining would allow ships to load grain and then “even with our assistance, proceed towards international waters.” He stated that vessels entering the ports would be inspected to ensure they were not carrying weapons. According to Mr. Peskov, the Russian side will not use demined corridors for offensive operations against seaside cities.

Russian officials have expressed willingness to ease the blockade in exchange for the lifting of sanctions against Moscow. Ukraine has questioned whether Russia can be trusted, and officials in the United States and the United Kingdom have expressed early opposition to such a deal.

Mykhailo Podolyak, an adviser to Ukrainian President Volodymyr Zelensky, said of Russian offers to ease grain exports: “Swearing that it does not want a food crisis, but destroying [Ukrainian] grain terminals.” “Does anyone believe the Kremlin’s promises?”

Russia’s Foreign Ministry announced sanctions against dozens of US citizens in response to US sanctions against Russians. The list of 61 Americans released by the ministry late Monday includes U.S. officials as well as current and former executives at large U.S. corporations such as Delta Air Lines Inc. CEO Edward Bastian, Universal Pictures President Peter Cramer, and Netflix Inc. CEO Reed Hastings. Among those facing sanctions is Treasury Secretary Janet Yellen.

Meanwhile, some Ukrainian families were preparing to receive the remains of fighters killed in the battle for Mariupol, which culminated in a siege of the Azovstal steel plant. According to an organization representing fighters’ families, forensic experts are working to identify 160 bodies handed over by Russia as part of a trade with Ukraine, one-third of whom were members of the regiment that defended the steel plant in Mariupol.

While diplomats sought alternative export routes for the country’s grain, Ukrainian forces held out in the eastern city of Severodonetsk, which had been targeted by Russia’s offensive. Over the weekend, Mr. Zelensky paid a rare visit to the front lines near the city, as Ukraine awaits heavier weaponry from the West, including long-range rocket systems from the United States, which it hopes will help blunt Russian artillery.

The governor of the Luhansk region, where Severodonetsk is located, Serhiy Haidai, said on Tuesday that street fighting continued more than a week after Russian forces entered the city.

Russia has concentrated its firepower on the east since withdrawing from Ukraine’s capital and other areas of northern Ukraine in March, making slow progress toward its goal of seizing the entire Donbas area, which includes Luhansk and the neighboring Donetsk region. Simultaneously, Russian forces continue to shell border areas while striking strategic targets deeper inside Ukraine, such as railway infrastructure and grain-storage facilities.

Mr. Michel stated that he witnessed millions of tons of grain and wheat stuck in containers and ships at the Ukrainian Black Sea port of Odessa a few weeks ago. Mr. Michel claims that Russian attacks on transportation infrastructure and grain storage facilities, as well as tanks, bombs, and mines, are preventing Ukraine from planting and harvesting.