Ukrainian forces have reclaimed large swaths of the south and east portions of their territory, dealing a blow to Russia’s invasion in a surprise counteroffensive.

Aided by billions of U.S. taxpayer dollars’ worth of increasingly powerful Western weapons, Ukraine has recaptured hundreds of miles of the eastern Kharkiv region, according to Business Insider.

The Russian army occupied much of the region during the initial offensive, which began in February and transported Russian soldiers within a few kilometers of essential cities like Kharkiv and Kyiv. The counterattack caught Russian soldiers off guard.

Residents of Zaliznychne, a tiny village 37 miles east of Kharkiv, reported that half of the Russian soldiers stationed there fled in their vehicles in the early hours of the offensive. They also claimed that many of those who stayed disguised themselves as locals to avoid detection by Ukrainian drones, The Washington Post reported.

CLICK HERE TO GET THE DALLAS EXPRESS APP

“Hell on Earth: our Defenders shared some images of how Vysokopillya in the Kherson region was liberated,” tweeted Anton Gerashchenko, advisor to the minister of internal affairs of Ukraine. “The village was on the verge of a humanitarian catastrophe. Russia will pay for it.”

General Valerii Zaluzhnyy, Ukraine’s military chief, said in a speech on Sunday that Ukrainian forces had liberated more than 1,100 square miles since the beginning of September, forcing Russian troops to withdraw from the northeastern Kharkiv region.

“Well, our 200 days fall on the September 11,” she said. “And we know this pain, and we feel this pain in Ukraine. We know how it is when terrorists attack you at home. So we always have to keep in mind that Russia still can do a lot of damage. But we don’t have any other choice; we will advance.”

Russian official Vitaly Ganchev told the state-owned Rossiya-24 television channel on September 12 that Ukrainian forces outnumbered Russian troops eight-to-one and had broken through to the Russian border, USA Today reported.

“The situation is getting worse by the hour,” he told the outlet.

Russia’s defense ministry announced that troops would be withdrawn from the Balakliya and Izyum areas but sent to the Donbas region of eastern Ukraine. This territory comprises two separatist regions that Russia has declared sovereign; Putin claimed in February that the invasion of Ukraine was a “special military operation to liberate Donbas.”