KYIV — Ukraine’s top general on Tuesday called for mobilizing more troops, a rare acknowledgment of heavy casualties after nearly two years of war with Russia.

In his first news conference since Russia’s invasion in February 2022, Gen. Valery Zaluzhny also conceded that Ukrainian troops have largely withdrawn from the eastern Ukrainian town of Marinka. The loss of the small settlement, now in ruins, is unlikely to have a significant impact on the larger battlefield but is nonetheless a sign that Russian forces have seized the initiative after Ukraine’s disappointing counteroffensive stalled with the coming of winter.

In what could be a major blow against Russia’s already damaged Black Sea Fleet, however, Ukraine said Tuesday that it had destroyed a large Russian landing ship docked in a Crimean port in an overnight attack. Russian officials confirmed the attack but said only that the ship and some surrounding buildings had been damaged. The Washington Post could not independently confirm the scale of the damage.

The Ukrainian air force said on its Telegram channel that it attacked the port of Feodosia around 2:30 a.m. local time. The port is in eastern Crimea, the contested peninsula that Moscow annexed in 2014 and has occupied since.

With the war largely at a stalemate, mobilization for what’s expected to be a long fight has been a prominent topic of discussion here. The text of a draft law posted on the website of Ukraine’s parliament late Monday proposed lowering the conscription age from 27 to 25.

President Volodymyr Zelensky said last week that Ukraine’s military leadership had proposed drafting up to 500,000 more troops. Adding another half-million soldiers or so, Zelensky said, would cost more than $13 billion. “This is a very serious number,” Zelensky said, adding that he wanted to hear more justification for why so many people should be mobilized.

Zaluzhny emphasized Tuesday that he hadn’t said anything about a “need for 500,000 or 400,000” soldiers — only a “general need.” To bring home soldiers who’d enlisted at the start of Russia’s invasion, he said, Ukraine needed to start training more soldiers now.

“Our needs are resources,” Zaluzhny said. “It’s weapons, it’s ammunition, it’s people. We calculate all of this in formulating our needs — people who we have lost, people who we could lose in the next year.”

How to fill the ranks has been a source of growing tension between Zaluzhny and Zelensky. Zelensky has so far declined to approve new draft measures without a war plan that includes the demobilization of already active soldiers.

“As of now, I did not see demobilization in their plan. And that is a number one question, an issue of justice for those fighting at the war front for so long,” Zelensky said last week.

But Zaluzhny pushed back against questions about imminent demobilization, adding that he hoped that in 2025 — after three years of service for those who joined the fight at the start of Russia’s 2022 invasion — he’d be able to “replace these people who are currently doing their jobs in extremely difficult conditions.”

Even providing rest for current troops, he acknowledged, was proving difficult. To comply with a law mandating that soldiers rotate out after six months, Zaluzhny said, he would need “at least two times more troops” — and even more if Russian launched a new onslaught.

“If we’re working with demobilization after 36 months, then more likely than not, we have to start the process of preparing people of conscription age already next year,” he said.

Ukraine’s military is believed to have about 1 million members in its ranks, though the number has not been publicly disclosed. Kyiv considers its casualty figures a state secret, but U.S. officials have estimated that more than 120,000 Ukrainian soldiers have been killed or wounded, far fewer than Russia, which also benefits from a larger army.

Next year, Zaluzhny assured, would be different, though he declined to give any specifics. “We only have to fight,” he said.

Gerrit De Vynck and Mary Ilyushina contributed to this report.

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