Kyiv, Ukraine(CNN) Ukrainian forces swept into the key city of Kherson on Friday as Russian troops retreated to the east, delivering a major victory to Kyiv and marking one of the biggest setbacks for President Vladimir Putin since his invasion began.
Elated civilians who had survived months of Russian occupation descended on Kherson's central square, hugging newly arrived Ukrainian soldiers, snapping selfies with them, and waving Ukrainian flags.
Footage of the jubilant scenes emerged hours after Russia announced it had withdrawn from the west bank of the Dnipro River in the strategic southern region of Kherson, leaving the regional capital of Kherson and surrounding areas to the Ukrainians.
The retreat represents a major blow for Putin's war effort in Ukraine. Kherson was the only Ukrainian regional capital that Russian forces had captured since February's invasion. Their withdrawal east across the Dnipro cedes large swathes of land that Russia has occupied since the early days of the war, and that Putin had formally declared as Russian territory just five weeks ago.
"The Ukrainian flag is raised in Kherson city. From now on, the Ukrainian flag will appear on all buildings in Kherson. This is what we have dreamed of from the first days of occupation," said Serhiy Khlan, a member of Ukraine's Kherson regional council.
On Friday evening, Ukraine's President Volodymyr Zelensky posted a night-time video of celebrations in Kherson city, where a crowd was waving flags and chanting "ZSU," the Ukrainian acronym for the armed forces.
He called it "a historic day" for Ukraine. "We are returning the south of our country, we are returning Kherson."
"As of now, our defenders are on the outskirts of the city. Just a little more to go and we will enter. But special units are already in the city," Zelensky said.
Zelensky appealed to any Russian soldiers still on the west bank to surrender.
"We guarantee that you will be treated in accordance with the law and international standards. And to those Russian military who disguised themselves in civilian clothes and are hiding somewhere, I want to say that you cannot hide. We will find you anyway," he said.
Ukrainian forces advanced through much of the Kherson region Friday, apparently encountering little or no resistance. Social media video from towns and villages throughout the region's west bank shows troops being greeted by civilians.
Russia's Defense Ministry announced earlier on Friday that its forces have completed their partial withdrawal from the Kherson region, after Moscow ordered the retreat Wednesday,
"In the Kherson direction, the move of Russian military units to the left bank of the Dnieper River was completed at 0500 [Moscow time] this morning," the ministry said on its official Telegram channel, using the Russian spelling for the river.
"Not a single piece of military equipment or weaponry was left behind on the right [west] bank," the statement added. "All Russian servicemen have moved to the left bank of the Dnieper."
Social media video suggests otherwise, with Russian tanks, armored vehicles and crates of ammunition displayed by Ukrainian troops.
Ukraine has asserted that it carried out attacks against Russian troop concentrations that were withdrawing, but the Russian Defense Ministry said in a statement later on Friday that "despite the attempts of the enemy to disrupt the transfer of Russian troops, no losses among personnel, weapons, military equipment and materiel were allowed."
It also claimed that the Ukrainian advance had been held back for several days, and that "manpower and military equipment of the Armed Forces of Ukraine on the right bank of the Dnieper are being hit by fire."
Ukraine has not reported any incoming fire from the east bank Friday but said a missile attack on the city of Mykolaiv, close to the border with Kherson, killed seven people early Friday.
Earlier Friday, the Ukrainian military's southern operational command said Russian forces had been "urgently loading into boats that seem suitable for crossing and trying to escape" across the river.
It was unclear whether all Russian troops had left Kherson and the wider region; Khlan said the city was "almost under the control of the Armed Forces of Ukraine" but warned that some Russian troops may have remained behind in civilian clothing.
He cautioned that many Russian troops "threw away their military uniforms, and are now hiding with civilian clothes on."
"They will be plotting provocations, false-flag operations in the city," he said. "There is a lot of work ahead on demining and clearing the city." Residents of Kherson city with whom CNN has spoken in recent weeks confirmed that many Russian soldiers were using civilian clothing.
Ukraine's military said it would proceed cautiously through Kherson region, and warned Russian troops were mining roads and destroying critical infrastructure as they retreated from the region.
"The Russian invaders continue their looting of settlements from which they are retreating," spokesman for the General Staff of Ukraine's Armed Forces Oleksandr Shtupun said. "The enemy is also trying to damage power lines, other transport and critical infrastructure facilities of Kherson region."
Images and video on social media Friday also showed that the Antonivskyi Bridge, the main conduit over the Dnipro in the Kherson region, had been destroyed.
At least seven bridges in total, four of them crossing the River Dnipro, have been destroyed in the last 24 hours, Maxar Technologies satellite images and other photos show.
Two bridges, a vehicle and a railroad, that sit atop a dam at Nova Kakhovka were among those destroyed.
Water is flowing out of three sluice gates at the critical dam, which spans the Dnipro river, according to satellite images from Maxar Technologies obtained by CNN.
It's unclear how the latest damage, which is close to the west bank, was caused. Local Telegram channels reported Thursday night the sound of explosions around the dam. Ukrainian forces do not appear they have taken control of the dam, which could cause considerable damage in the region if breached.
Alexander Kots, a reporter for the Russian pro-government tabloid Komsomolskaya Pravda embedded with Russian forces, posted a video on his Telegram channel standing on the crossing, showing the entire center section of the bridge destroyed. "Behind me are the two collapsed spans of (the) bridge," Kots said. "They were likely blown up during the withdrawal of the Russian group of forces from the right bank to the left," or western bank to eastern bank.
Russian forces have ceded about 40% of the Kherson region, which straddles the Dnipro, within a few days.
Now that Ukrainian forces have recaptured Kherson as far as the Dnipro river, the two sides face each other across the river over a distance of some 250 kilometers -- from the area around the Zaporizhzhia nuclear power plant to the edge of the Black Sea.
As Russian forces have fled, Ukrainian troops have pushed forward in their wake, capturing dozens of villages and settlements in Kherson region above the Dnipro.
The Ukrainian military on Friday recaptured another part of Kherson region, the village of Tyahinka near the strategic town of Nova Kakhovka, despite Russian forces destroying bridges to the village.
A video circulating on social media on Friday, geolocated and authenticated by CNN, showed Ukrainian forces being greeted by residents on the main highway in Tyahinka. The village is just 14 miles (20 km) west of the hydroelectric dam and bridges that stretch across the Dnipro river at Nova Kakhovka.
A number of photos, also geolocated and authenticated by CNN, show that the Ukrainian forces were able to make their way into the village despite the main highway's bridge and a pedestrian bridge being destroyed by the Russians as they withdrew. Dozens of bridges across the Kherson region have been destroyed or disabled during the conflict.
Residents of the town of Bilozerka, on the western outskirts of Kherson city, raised a Ukrainian flag and ripped down Russian propaganda billboards on Friday, according to videos on social media geolocated by CNN.
One video showed a Ukrainian flag flying over a World War II memorial, while another showed residents tearing down a propaganda billboards with a young girl holding a Russian flag, which read: "Russia is here forever."
The scenes of people greeting Ukrainian troops across the region were in sharp contrast to claims by Russian-appointed officials in Kherson six weeks ago that 87% of voters there supported integration into the Russian Federation, in a referendum widely condemned by the international community as a sham. Kherson was one of four Ukrainian regions illegally annexed by Russia in September.
Kyiv officials had warned that retreating Russian troops could turn the regional capital of Kherson into a "city of death" on the way out, and an official in southern Ukraine warned residents Friday to be wary of quickly returning to recently liberated territory due to the threat of mines.
"There are a lot of mines in the liberated territories and settlements," Vitaliy Kim, head of Mykolaiv region military administration, said on Telegram. "Don't go there for no reason. There are casualties."
Putin's spokesperson on Friday insisted that the region remains part of Russia, despite the Russian withdrawal.
"This is a subject of the Russian Federation," Dmitry Peskov said during a regular briefing with journalists. "It has been legally fixed and defined. There can be no changes here."
Russia still controls a large portion of the Kherson region -- the area east of the Dnipro River.
When asked directly whether Russia's retreat was "humiliating" for President Vladimir Putin, Peskov replied: "No."