KYIV, Ukraine — Ukrainian forces advanced on the Russian-occupied city of Kherson in the south on Friday, and the two sides battled over smaller cities in the east, as the armies fought not only each other but also a thick clay muck that can swallow vehicles’ wheels and soldiers’ boots whole.
It is the muddy season, called “bezdorizhzhya” in Ukrainian and “rasputitsa” in Russian. In any language it turns warfare — especially offensive operations — into a slow, arduous slog, exposing troops and equipment to enemy fire.
In the southern Kherson region, a largely agricultural area where wide-open plains are crisscrossed with irrigation canals, the chilly, wet weather is making conditions particularly difficult, slowing Ukraine’s offensive. Ill-prepared Russian troops are suffering from “the lack of warm clothes,” Ukraine’s military command said in a statement on Friday, leading to “widespread theft and looting.”
Muddy season strikes twice a year in many rural areas of Eastern Europe, with the spring thaw and again with autumn rains, before the winter freeze. Where roads are unpaved, it can be immobilizing. The same conditions hampered Napoleon’s invasion of Russia in 1812, Hitler’s invasion of the Soviet Union in 1941 and the Russian invasion of Ukraine early this year.
Despite the conditions, both sides continued preparations for a long-threatened Ukrainian southern offensive on the strategic port city of Kherson. Russia has moved an additional 1,000 troops, drawn from those swept up in its recent mobilization, into the city to prepare for its defense, even as it evacuates civilians, the Ukrainian military said on Friday.
Sergei K. Shoigu, the Russian defense minister, said on Friday that Russia had completed that mobilization effort, announced last month after heavy Russian casualties and battlefield setbacks. Of a total draft of 300,000 people, he said, 82,000 had been sent to Ukraine while the rest were in training. His claims could not be independently confirmed.
At a meeting with Mr. Shoigu, President Vladimir V. Putin made a rare acknowledgment that the war in Ukraine had revealed the need “to make corrections” in the faltering Russian military, according to a Kremlin readout.
The conscription sent shock waves through Russian society, which Mr. Putin had tried to shield from the consequences of war, and it was, by the Kremlin’s own admission, badly managed. The draft prompted a mass exodus of young men from Russia, and — though open criticism of the Kremlin is increasingly rare and dangerous — widespread protests and even questioning of the invasion on state TV. At the same time, hawks have complained that the war is not being waged vigorously enough.
Ksenia Sobchak, an occasional critic of Mr. Putin and a media star once called the “Russian Paris Hilton,” left the country and entered Lithuania on Thursday, the Lithuanian government said, shortly after Russian security officers searched her home and arrested an executive of her media company.
A mercurial figure, Ms. Sobchak ran for president against Mr. Putin in 2018, in a candidacy that critics dismissed as a move cooked up with the Kremlin to give the appearance of real choice in the contest. Prone to flip-flopping between mild criticism of the government and cheerleading, Ms. Sobchak, the goddaughter of Mr. Putin, is often mocked by more determined dissidents.
Fighting also raged Friday in eastern Ukraine, where Ukrainian forces are trying to surround the strategically important city of Kreminna in the Luhansk region. About 30 miles to the southwest, the Russians continued their frontal assaults on the battered city of Bakhmut, in the Donetsk region.
In April, Moscow’s forces captured Kreminna, home to about 18,000 people before the war, and by July had taken full control of Luhansk. But a Ukrainian counteroffensive that started in early September has regained a foothold in the region. Kreminna sits astride a vital Russian logistical artery used to supply units in Luhansk and Donetsk, so its loss would further damage Russia’s faltering war effort.
Russian military bloggers released video footage of Moscow’s forces employing TOS-1 thermobaric multiple-launch rocket systems to slow the Ukrainian advance. Thermobaric weapons, also called fuel-air explosives or vacuum bombs, create much larger blast waves than traditional explosives, doing indiscriminate damage.
The Institute for the Study of War, a Washington-based research organization, said the use of the powerful system could indicate either that the Russians are prioritizing the area, “or that Russian forces lack sufficient artillery systems or ammunition more appropriate for standard fire missions.”
Ukraine’s military governor of the Luhansk region, Serhiy Haidai, underscored the challenges for its forces in the area, noting that, as elsewhere, heavy rains had complicated the ability to move equipment. And since the swift advance of Ukrainian forces across northeastern Ukraine last month, he said, the Russians have had time to bring up reserves, fortify defenses, damage bridges and plant mines.
Around Bakhmut, Russian forces have failed to gain significant ground despite months of daily bombardment. President Volodymyr Zelensky of Ukraine said this week that fighting there was some of the heaviest in the war.
“The craziness of the Russian command is now most visible there: Day after day for months, they drive people there to death, concentrate the maximum power of artillery strikes there,” he said.
Military analysts have said the city, with a prewar population of 70,000, holds only minimal strategic value and that the Russian efforts there are better explained by competition among disparate elements of the Russian military.
The Bakhmut offensive is being led by fighters from the Wagner mercenary group, and its founder, Yevgeny V. Prigozhin, has been seeking a higher profile as the military effort has floundered.
The Ukrainian military has sought to undermine already-weak Russian morale by releasing a steady stream of intercepted communications between Russian soldiers complaining about grim conditions. The Ukrainian military said on Friday that “the unsatisfactory state of military equipment” on the Russian side had led to “unique cases of desertion and surrender.” That claim could not be independently verified.
In Kherson province, Russian forces hold the territory east of the Dnipro River, but their foothold on the west bank, including the city of Kherson, is imperiled. Ukrainian forces have destroyed bridges across the river, making reinforcement and resupply difficult for the thousands of Russian troops in the city.
Russian proxy officials in Kherson said on Friday that the civilian evacuation of the city was complete, a claim that could not be verified. It had some 280,000 people before the war, but as in many of the cities and towns caught in the fighting, much of the population fled months ago, primarily to Ukrainian-held territory.
For days the Kremlin-appointed regional administration has been relocating its operations across the river and urging civilians to leave eastward, as well — while Russian troops have blocked most routes for people to move north or west, to lands still held by Ukraine.
Ukraine’s claim of more Russian troops moving into the city could not be independently verified. The British Defense Ministry said on Friday in an intelligence update that Russia had most likely supplemented its forces on the west bank of the Dnipro with reservists, but noted that this was from a very “low level of manning.”
Kherson, the first city captured by Russia after the February invasion, is the gateway to both Russian-held Crimea in the south and Ukraine’s Black Sea ports to the west, including Odesa. Its loss would be a severe military and symbolic blow for Mr. Putin, who has rejected requests from his commanders that they be allowed to retreat from the city.
But Brig. Gen. Oleksii Hromov, of the Ukrainian general staff, said that even as Russians took steps to defend the city, they were preparing in case they had to quickly abandon their positions west of the Dnipro.
Ukrainian officials have claimed repeatedly that Russia was preparing to damage or destroy a major hydroelectric dam on the Dnipro upstream of Kherson, possibly to cover a retreat, which would cause widespread flooding, further devastate Ukraine’s electrical grid and deprive the Zaporizhzhia Nuclear Power Plant of vital water for cooling.
But Mr. Zelensky, speaking to the Italian newspaper Corriere della Sera this week, said that he did not see evidence of Russian forces fleeing Kherson. He said they might be trying to lure Ukrainians into advancing too quickly.
“They are not ready to leave Kherson,” he said, adding that the longer it takes Ukrainian forces to drive the Russians out of the city, the more dire the conditions will be for any civilians who remain.
“It’s difficult because the price is people,” he said.
Reporting was contributed by Richard Pérez-Peña, Ivan Nechepurenko and Anatoly Kurmanaev.