Ukrainian forces were closing in on the outskirts of Kherson city as Russia said on Thursday it had begun the retreat from the southern city that it announced the previous day. Hours after Ukraine claimed the liberation of the key town of Snihurivka, images emerged of relaxed-looking soldiers from Ukraine’s 28th Mechanised Brigade with a Ukrainian flag in Kyslivka, a village just outside Klapaya and about nine miles (15km) from Kherson’s city centre. The Russian defence ministry, confirming that its withdrawal was under way, said: “The Russian troop units are manoeuvring to a prepared position on the left bank of the Dnipro River in strict accordance with the approved plan.” Witness reports said Russian forces were still visible in Kherson, with Ukrainian troops continuing their advance from three directions – from the north, east and west – as the large pocket around the city once held by Russian forces appeared to be shrinking. Vadym Skibitsky, Ukraine’s deputy military intelligence chief, estimated over half of the Russian forces that had been stationed on the right bank were still there – a force that had previously been put at 20,000. “The most recent information we have is the 4th Tactical Military Base has supposedly been transferred to the left bank. The rest are still there, fighting, conducting military activities with the aim of providing cover for others to leave,” added Skibitsky. According to Skibitsky, the Russians are retreating from the second line of defence that they were pushed back to by Ukrainian forces in early October. But they have built a defence line around Kherson city – and he said “time will tell” whether they will choose to defend the city. Late on Thursday there were reports of incoming shelling explosions around the Nova Kakhovka, a 30-metre hydroelectric facility which Kyiv has repeatedly warned could be targeted by the Russians. Among the areas recaptured by Ukrainians on Thursday was the town of Snihurivka with footage showing a group of Ukrainian soldiers in Snihurivka as one of them announced: “Today, on 10 November, Snihurivka was liberated by the forces of the 131st Separate Intelligence Battalion. Glory to Ukraine!” A small group of civilians applauded nearby. Snihurivka, situated about 20 miles north of Kherson, was an important logistics hub for Russian forces on the west bank of the Dnipro and acted as an anchor for the Russian defensive lines there. Russia’s defence minister, Sergei Shoigu, announced on Wednesday that Russian forces would retreat from the west bank of the Dnipro, which includes Kherson, the only regional capital that Moscow had captured since invading Ukraine in February. Despite Russia announcing its withdrawal from the area, Kyiv has said it is wary of rushing in and warned it may be a trap by the Kremlin. Brig Gen Oleksiy Gromov told a briefing that the Ukrainian armed forces’ actions had left Russian forces no option but to withdraw. “But at the moment we can neither confirm nor deny the information about the so-called Russian withdrawal of troops from Kherson. We will continue our offensive operation in accordance with our plan,” he said. While the announcement by Moscow that it was abandoning its defence of Kherson has been greeted with jubilation in Ukraine, Ukraine’s military and key officials have been far more cautious, warning that the posture of Russian forces remained unclear. One senior adviser to Ukraine’s president said on Thursday that Russia wanted to turn Kherson into a “city of death”. Mykhailo Podolyak accused Russia of mining everything from flats to sewers and planning to shell Kherson from the other side of the Dnipro. “RF [Russia] wants to turn Kherson into a ‘city of death’. The Russian military mines everything they can: apartments, sewers. Artillery on the left bank plans to turn the city into ruins,” Podolyak tweeted. “This is what [the] ‘Russian world’ looks like: came, robbed, celebrated, killed ‘witnesses’, left ruins and left.” On Thursday, people in Kherson reported still seeing Russian forces in the city, although it was not clear how many remained. Yevhen Hilin, the head of the NGO City of Power, which has been delivering aid and helping people evacuate Kherson since the invasion, said local people who it had been in touch with described “a striking silence and calm in the city”. He added: “There are no roadblocks. Only single vehicles of the occupiers drive by; people try not to leave their homes because sometimes shelling is heard in the city.” Pavel, another resident who did not want to give his surname, told the Guardian: “We have been without electricity, water and heating for almost 24 hours. There is barely any phone connection. It is quiet in the city. The Russians have removed all their flags.” Video posted by Russian soldiers retreating across the Dnipro appeared to confirm that at least some troops had already withdrawn. One video posted on Russian Telegram channels appeared to show a night-time convoy of Russian vehicles described as heading for a river crossing. In another video, two soldiers speak to camera during their own crossing on a pontoon ferry next to the damaged Antonivsky Bridge. It was not clear on what day it was filmed. “So this is a historical moment. It’s quite difficult,” says one of the soldiers, sighing. Today we woke up very early … we’re crossing to the other bank of the Dnipro. It’s the first time I’ve seen the river. Yes. It’s wide. It’s the first time I’ve seen Kherson. Now it’s clear to me why what is happening is happening. Defending the city with these supply lines would be utter madness.” The second soldiers speaks: “We saw many banners here. ‘Russia is here for ever.’ We’ll see what’s going to happen next.”