The town, which once had a population of 32,000, fell to Russia on Saturday, Putin's biggest battlefield victory since Russian forces captured the city of Bakhmut in May 2023.

Television footage released by Russia's defence ministry showed that almost every house in Avdiivka had been branded with war.

Putin said on Tuesday the Ukrainian order to withdraw from the town had been announced after Ukrainian troops had already begun to flee in chaos. He said that all captured Ukrainian soldiers should be accorded their rights under international conventions on prisoners.

"As for the overall situation in Avdiivka, this is an absolute success, I congratulate you. It needs to be built on," Putin told Defence Minister Sergei Shoigu in the Kremlin.

"But that development must be well-prepared, provided with personnel, weapons, equipment and ammunition," Putin said. "It seems to be self-evident, but nevertheless I draw your attention to it."

Ukrainian Foreign Minister Dmytro Kuleba told CNN that Avdiivka would not have fallen had Kyiv received weapons held up by the U.S. Congress' failure to approve a large aid package.

"We wouldn't (have lost) Avdiivka if we had all the artillery ammunition that we needed to defend it. Russia does not intend to pause or withdraw...Once Avdiivka is under their control, they undoubtedly will choose another city and begin to storm it," Kuleba said.

Ukrainian troops, he said, were "making miracles...but the reason they have to sacrifice themselves and die is that someone is still debating a decision. I want everyone to remember that every day of debate in one place means another death in another place."

The U.S. Senate this month passed a $95 billion aid package that includes funds for Ukraine, but House of Representatives Speaker Mike Johnson has declined to bring it up for a vote on the floor of the House.

MONTHS OF FIGHTING

Ukraine said it withdrew its soldiers to save them from being fully surrounded after months of fierce fighting. The Ukrainian military said there had been casualties, but that the situation had stabilised somewhat after the retreat.

Each side said the other had suffered huge losses.

After the failure of Ukraine to pierce Russian front lines in the east and south last year, Moscow has been trying to grind down Ukrainian forces just as Kyiv ponders a major new mobilisation.

Ukrainian President Volodymyr Zelenskiy appointed a new commander last week to run the war.

Putin sent tens of thousands of troops into Ukraine in February 2022, triggering full-scale war after eight years of conflict in eastern Ukraine between Ukrainian forces on one side and pro-Russian Ukrainians and Russian proxies on the other.

Avdiivka, called Avdeyevka by Russians, has endured a decade of conflict. It holds particular symbolism for Russia as it was briefly taken in 2014 by Moscow-backed separatists who seized a swathe of eastern Ukraine, but was then recaptured by Ukrainian troops who built extensive fortifications.

Avdiivka sits in the industrial Donbas region, 15 km (9 miles) north of the Russian-controlled Ukrainian city of Donetsk. Before the war, Avdiivka's Soviet-era coke plant was one of Europe's biggest.

Shoigu said Russian forces had also taken control of the village of Krynky in Ukraine's southern Kherson region. Ukraine's southern military command said its troops had held their positions on the left bank of the River Dnipro and that Russian attacks were unsuccessful.

Neither side gives death tolls for the war.

(Reporting by Reuters; editing by Andrew Osborn, Ron Popeski and Mark Heinrich)

By Guy Faulconbridge