KYIV, Ukraine — After setbacks on the battlefield, Moscow pressed to consolidate its hold over occupied Ukrainian territory on Tuesday, with the Kremlin’s proxy officials across eastern and southern Ukraine abruptly scheduling referendums to formally join Russia.
One by one, Moscow-installed officials in four Ukrainian regions announced plans to hold the votes beginning on Friday. The plans are certain to deepen the international condemnation of Russia’s invasion, which President Vladimir V. Putin launched in February with the objective of seizing lands that he claims are rightfully Russian.
U.S. officials have warned for months that Mr. Putin could use sham referendums in occupied areas — which many residents have fled amid fierce fighting — to try to legitimize the illegal annexation of parts of Ukraine.
On Tuesday, Russia’s foreign minister, Sergey V. Lavrov, said the referendums would allow the territories to decide their future. “The current situation confirms that they want to be the masters of their future,” Mr. Lavrov told Rossiya-1, a state television network.
The scheduling of the votes, which appeared to be coordinated, came after Ukrainian forces routed Russians from the northeast in recent weeks and are on the offensive in the east and south. Russia has lost tens of thousands of troops, is struggling to recruit new soldiers and is facing a growing backlash, even from some allies, over its prolonged and bloody invasion.
Ukraine said the moves signaled desperation by Russia. Mykhailo Podolyak, a senior adviser to President Volodymyr Zelensky of Ukraine, said that talk about annexation was little more than a “sedative” for the Russian audience as Moscow tried to make sense of its losses on the battlefield.
Any so-called referendum, he added, would not stop “HIMARS and the armed forces from destroying occupiers on our land,” referring to an American-supplied missile system that has helped the Ukrainians target Russian forces.
Ukraine’s foreign minister, Dmytro Kuleba, dismissed the plans for “sham ‘referendums’” and said: “Russia has been and remains an aggressor illegally occupying parts of Ukrainian land. Ukraine has every right to liberate its territories and will keep liberating them whatever Russia has to say.”
Russian proxy officials in four regions — Donetsk and Luhansk in the east, and Kherson and Zaporizhzhia in the south — announced plans to hold referendums over four days beginning on Friday. Mr. Putin recognized separatist enclaves in Donetsk and Luhansk as independent from Ukraine just before launching his invasion, but Russia does not fully control any of the four regions.
On Tuesday, Russia’s Central Election Commission, the country’s main elections authority, said it would help separatist entities to conduct the referendums. Nikolai Bulayev, deputy chair of the commission, told Interfax, a Russian news agency, that the agency would send observers there and open polling stations in Russia — ostensibly for residents of occupied areas who have fled across the border or have been forcibly deported.
Russia’s State Duma speaker, Vyacheslav Volodin, endorsed the plans for referendums, saying on Tuesday during a session of the lower chamber of Russia’s Parliament: “If during a direct vote they would say that they want to become part of Russia, we will support them.”
And Dmitri Medvedev, Russia’s former president and a close ally of Mr. Putin’s, said on Tuesday that it was “essential” to bring the eastern regions of Ukraine into the Russian Federation, saying that “the geopolitical transformation in the world will become irreversible.”
In the months since Russia’s invasion, Kremlin-backed officials across the occupied territories have repeatedly announced plans for referendums, only to see those plans fail to come to fruition as they were greeted with little public support and fighting made it impossible to hold a vote. Ukrainian special forces working with local partisans have targeted proxy officials responsible for carrying out referendum plans.
On Sept. 8, for instance, Ukrainian resistance fighters in the occupied city of Melitopol blew up the headquarters of the “We Are Together With Russia” movement, destroying ballots and other material related to a referendum. The head of the Russian-backed local administration, Vladimir Rogov, called it a terrorist attack.
In 2014, Russian forces invaded Crimea and Mr. Putin annexed it after newly installed officials hastily organized a secession referendum that was reported to have secured the support of 97 percent of voters, drawing international accusations of fraud.