By Jonathan Landay and Tom Balmforth
FRONTLINE WEST OF KHERSON, Ukraine/KYIV (Reuters) -Russian President Vladimir Putin publicly endorsed the evacuation of civilians from parts of Ukraine's southern Kherson region on Friday, the latest sign of Russia's retreat in one of the most bitterly contested areas in Ukraine.
"Now, of course, those who live in Kherson should be removed from the zone of the most dangerous actions, because the civilian population should not suffer," Putin told pro-Kremlin activists as he marked Russia's Day of National Unity.
Moscow has already been ferrying people out of an area it controls in Kherson on the west bank of the Dnipro River, and this week announced that the evacuation zone would also include a 15 km buffer area on the east bank. But the comments appear to be the first time Putin has endorsed the evacuations personally.
Russia says it has been taking residents to safety from the path of a Ukrainian advance. Kyiv says the measures have included forced deportations of civilians out of Russian-occupied territory, a war crime, which Russia denies.
Putin's comments come as signs are emerging that Russia could be preparing to abandon its military foothold on the west bank of the Dnipro River, including Kherson's regional capital - potentially one of the biggest Russian retreats of the war.
On Thursday, Kirill Stremousov, deputy head of the Russian-installed occupation administration in Kherson, said Russia was likely to pull its troops from the west bank. In later remarks, he was more equivocal, saying he hoped there would be no retreat but "we have to take some very difficult decisions".
Pictures have circulated on the internet showing the main administration building in Kherson city with Russia's flag no longer flying atop it. Kyiv has been wary, saying such signs could be Russian deception to lure Ukrainian troops into a trap.
A 24-hour curfew was imposed on the city on Friday, Stremousov said, adding the measure was necessary to defend Kherson from a likely Ukrainian offensive.
Ukrainian soldiers in a mechanized infantry company dug in on a tree line at the front west of Kherson city were confident the Russians would eventually retreat, but would fight as they fall back, auguring a potentially bloody battle for the city.
Vitalyi, 48, the company's deputy commander, said recent moves by the Russians to beef up their defences appeared aimed at protecting a withdrawal rather than holding on to Kherson.
"They have dug into every field," he said, as his men took advantage of the unusually mild weather to improve bunkers and clean their weapons amid thumps of intermittent artillery fire.
"They have large amounts of tanks and people, but I don't think they have a realistic plan to stay more than one or two weeks," he said.
One of his soldiers, Vladyslav, 27, said he expected the Russians would fight: "We will fight as well. We have no where else to go. This is our home. This is our land."
The regional capital, which is located on the west bank at the mouth of the Dnipro, is the only big city Russia has captured intact since its invasion in February. Its loss for Russian forces would be one of the severest blows of the war.
The surrounding province controls land access to Russian-occupied Crimea, and securing it was one of the few successes of an otherwise disastrous Russian campaign.
U.S. Defense Secretary Lloyd Austin said he "certainly" believed Ukrainian forces could retake the Russian-held area on the west bank, in perhaps his most optimistic comments on the counter-offensive to date.
"Most importantly, the Ukrainians believe they have the capability to do that. We have seen them engage in a very methodical but effective effort to take back their sovereign territory."
The Pentagon later announced $400 million worth of additional security assistance, including HAWK air defenses against Russian drones and cruise missiles.
A Western official, speaking on condition of anonymity, said some Russian military commanders had already moved across the river to the east, effectively abandoning the troops under their command on the opposite bank.
"We would assess that in Kherson, it's likely that most echelons of command have withdrawn now across the river to the east, leaving pretty demoralized and often in some cases leaderless troops to face off Ukrainians on the other side," the official said.
Vladimir Saldo, the Russian-installed head of the occupied province, has said it was evacuating civilians to facilitate "a layered defence" in order to repel Ukrainian attacks.
(Reporting by Reuters bureauxWriting by Peter Graff and Frank Jack Daniel Editing by Philippa Fletcher and Gareth Jones)