KYIV, Ukraine — The head of the Russian private military contractor Wagner claimed Thursday that his forces have started pulling out of Bakhmut, in eastern Ukraine, and handing over control to the Russian military, days after he said Wagner troops had captured the ruined city.

Yevgeny Prigozhin, Wagner’s millionaire owner with longtime links to Russian President Vladimir Putin, said in a video published on Telegram that the handover would be completed by June 1. There was no immediate comment from the Russian defense ministry.

It was not possible to independently verify whether Wagner’s pullout from the bombed-out city has begun, and the Ukrainian General Staff said Wednesday that heavy fighting was continuing inside the eastern city after a nine-month battle that killed tens of thousands of people.

Prigozhin’s Bakhmut triumph delivered a badly needed victory for Putin, whose invasion of Ukraine in February 2022 has lost momentum and now faces the possibility of a Ukrainian counteroffensive using advanced weapons supplied by Kyiv’s Western allies.

Top Ukrainian presidential advisor Mykhailo Podolyak said Thursday that Ukraine’s counteroffensive was already underway, cautioning that it should not be anticipated as a “single event” starting “at a specific hour of a specific day.”

Writing on Twitter, Podolyak said that “dozens of different actions to destroy Russian occupation forces” had “already been taking place yesterday, are taking place today and will continue tomorrow.”

Prigozhin has a long-running feud with the Russian military leadership, dating back to Wagner’s creation. He has also built a reputation for inflammatory — and often unverifiable — headline-grabbing statements.

During the 15-month war in Ukraine, he has repeatedly and publicly chastised Russia’s military leadership, accusing them of incompetence and failure to properly provision his troops as they spearheaded the battle for Bakhmut.

Wagner’s involvement in the capture of Bakhmut has added to Prigozhin’s standing, which he has used to set forth his personal views about the conduct of the war.

“Prigozhin is … using the perception that Wagner is responsible for the capture of Bakhmut to advocate for a preposterous level of influence over the Russian war effort in Ukraine,” the Institute for the Study of War, a Washington think tank, said.

His frequent critical commentary about Russia’s military performance is uncommon in Russia’s tightly controlled political system, in which only Putin can usually air such criticism.

His flat statement of what he would do over the next week in Bakhmut came a day after he again broke with the Kremlin line on Ukraine. He said its goal of demilitarizing the country has backfired, acknowledged Russian troops have killed civilians and agreed with Western estimates that he lost more than 20,000 men in the battle for Bakhmut.

Meanwhile, Russian unleashed a barrage of Iranian-made Shahed 36 drones against Kyiv in its 12th nighttime air assault on the Ukrainian capital this month but the city’s air defenses shot down all of them, Ukrainian authorities said Thursday.

The Kremlin’s forces also launched 30 airstrikes and 39 attacks from multiple rocket launchers as well as artillery and mortar attacks across Ukraine, the Ukrainian military said.

In Russia, meanwhile, the Foreign Ministry announced Thursday that five Swedish diplomats are to be expelled from the country.

According to the statement, the decision is a response to Stockholm’s “openly hostile step” to declare five employees of Russian foreign missions in Sweden “personae non grata” in April.

Moscow additionally announced its decision to close its consulate in Göteborg in September, as well as its “withdrawal of consent” to the activities of the Swedish consulate in St. Petersburg.