Moscow's biggest stronghold in northeastern Ukraine collapsed Saturday following a swift Ukrainian assault.

Moscow suffered its greatest setback since its soldiers were driven from the Ukrainian capital of Kyiv in March with the rapid fall of Izium in Kharkiv Province.

As hundreds of Russian forces retreated, they left behind ammo caches and other supplies, which Ukraine hailed as a turning point in the six-month-old conflict, Reuters reported.

Russia's defense ministry told soldiers to leave the area and strengthen operations elsewhere in Donetsk, according to the state-run TASS news agency.

Russia Suffers Devastating Setback

According to TASS, the director of Russia's administration in Kharkiv advised locals to leave the region and move to Russia to "save lives." Witnesses report traffic bottlenecks exiting the Russian-controlled area.

It would be a devastating setback for Russia, which Western intelligence services claim has incurred massive fatalities if the advances that have been recorded hold up. It would also be a huge boost for Ukraine, which is eager to demonstrate to the Western countries that continue to provide it with weaponry that it is deserving of their continuing backing.

Russian President Vladimir Putin has threatened to suspend all energy supplies to Europe if Brussels approves a proposal to regulate Russian oil export prices, putting pressure on Kyiv to make progress before winter.

Dmytro Kuleba, the foreign minister of Ukraine, stated in Kyiv that Ukrainian soldiers have proven they could destroy the Russian army using the armaments provided to them.

Kuleba noted: "And so I reiterate: the more weapons we receive, the faster we will win, and the faster this war will end."

Ukrainian SOF in Izyum pic.twitter.com/JixKDF6quo

— WarMonitor🇺🇦 (@WarMonitor3) September 10, 2022

President Volodymyr Zelensky stated in his nightly video message on Saturday that since the start of Ukraine's counteroffensive earlier this month, its military forces have reclaimed around 2,000 square kilometers (770 square miles) of land.

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Russian Reinforcements Fail

According to Russian military journalist Yevgeniy, Russian military headquarters used Mi-26 helicopters on Friday to re-deploy reserve soldiers to Kupyansk and Izium while bolstering forces in Kharkiv with personnel and armored vehicles.

But it didn't appear that the reinforcements had any impact. Izium and Kupyansk were both retaken, which was a significant tactical victory for Kyiv.

Izium, which is close to the line separating the Kharkiv and Donetsk provinces, had been occupied by Russia for more than five months and had grown into a key military post for the invasion forces. According to CNN, Russia used Izium to launch operations into Donetsk and Kupyansk, 30 miles north of Izium, to replenish its soldiers.

According to Kyiv, its soldiers have cut off a crucial Russian supply route that passed through the Kharkiv region and is now heading farther east. At the same time, the Ukrainian military said that Russian forces had suffered losses in the southern Ukrainian province of Kherson.

Even the government in Izium, which is supported by Russia, had to admit the retreat on Saturday. Vladislav Sokolov, head of the pro-Russian Izium city government, said the situation is "very difficult," per the Russian state news agency RIA.

President Vladimir Putin's decision to deploy reinforcements to Kharkiv, according to US Secretary of State Antony Blinken, highlights the considerable casualties Russia's troops are suffering.

He said there were a sizable number of Russian soldiers in Ukraine and that President Putin had shown he was willing to send many people there at great expense to Russia, as per a report from Al Jazeera.

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