Russia pulled back troops and civilian administrators from towns on the bank of the Dnipro River opposite Kherson on Tuesday, signs that Russia might be retreating further after surrendering its biggest Ukrainian prize last week.
Moscow followed its losses on the battlefield with apparent long range strikes on the capital Kyiv, where air raid sirens blared, two explosions were heard and columns of smoke could be seen rising from the ground.
Moscow had said last week it was pulling its troops across the wide Dnipro to positions that were easier to defend on the opposite bank, abandoning the only regional capital captured since its invasion in February.
But video images filmed in the town of Oleshky, across a collapsed bridge from Kherson, appeared to show Russian forces had abandoned bunkers there too. Further east, Russian-installed administrators said they were pulling out civil servants from Nova Kakhovka on the river bank next to a huge, strategic dam.
Natalya Humenyuk, a Ukrainian military spokesman, said Moscow appeared to be repositioning its artillery 15-20km further from the river, to protect its guns from Ukrainian counter strikes.
"There is a certain activity of enemy troops on the left bank of the Dnipro in terms of moving 15-20km away from the bank," she said. Russia had artillery still capable of striking Kherson from those new positions, but "we also have something to answer with", she said.
President Volodymyr Zelensky told world leaders there would be no let-up in Ukraine's military campaign to drive Russian troops out of his country.
"We will not allow Russia to wait it out, build up its forces, and then start a new series of terror and global destabilisation," he said in an address by video link to a summit of the G20 big economies in Indonesia.
"I am convinced now is the time when the Russian destructive war must and can be stopped."
Ukrainian forces mobbed by joyous residents swept into Kherson in recent days to claim the biggest prize of the war so far, a city that Russian President Vladimir Putin had proclaimed six weeks ago would be Russian forever.
Russia had said it was pulling its forces across the Dnipro to the opposite bank, where they could better defend captured territory including the approaches to the strategic Crimea peninsula, which Russia has held since 2014.
But in video filmed in Oleshky, across the river from Kherson on the main highway two hours' drive to Crimea, there was no sign of any Russian presence.
A driver raced down the deserted main road for miles at high speed without encountering a single Russian checkpoint or flag. Several bunkers set up along the road appeared to have been abandoned. The location of the video was confirmed by Reuters based on visible landmarks.
In Nova Kakhovka, site of a huge hydro-electric dam on the Dnipro that supplies Crimea's water, the Russian-installed administration said on Tuesday civil servants had left to escape shelling, "and were relocated to safe areas in the region".
There were no confirmed reports that Ukrainian troops had crossed the river to pursue the Russians. But some analysts said Ukraine might attempt to press its advantage on the battlefield, rather than take a so-called "operational pause" following the advances of recent days.
"Ukraine has the initiative and momentum and is dictating to the Russians where and when the next fight will be," said Philip Ingram, a former senior British military intelligence officer.
On Monday, Zelensky visited Kherson to celebrate the victory there, shaking hands with soldiers and waving to civilians. He said Ukraine had already gathered evidence of at least 400 war crimes committed by Russian troops during their eight month occupation, including killings and abductions.
Russia, for its part, has lately said it is focusing on eastern Ukraine, where it claimed to have captured Pavlivka, a frontline village in Donetsk region. Kyiv says Russia has endured huge losses in assaults in the east with few gains.
The war was a central focus of the G20 summit, at which Western leaders denounced Moscow. Russia is a member and Ukraine is not, but Russian President Vladimir Putin stayed home.
In his speech to the world leaders on the Indonesian island of Bali, Zelensky described a peace proposal under which Russia would withdraw all its forces from Ukraine, free all prisoners and reaffirm Ukraine's territorial integrity.
He would indefinitely extend a programme to safeguard Ukrainian grain exports, and expand it to the port of Mykolaiv, beyond reach of Russian guns after the Kherson advance.
"Please choose your path for leadership - and together we will surely implement the peace formula," he said.
The US expects the G20 to condemn Russia's war in Ukraine and its impact on the global economy, a senior US official said. Russia's membership makes consensus on Ukraine unlikely, and the official declined to say what form the condemnation would take.
Foreign Minister Sergei Lavrov, heading Russia's delegation in Putin's absence, accused the West of trying to politicise a declaration from the summit by including language condemning Russia's actions in a draft declaration.