KYIV, UKRAINE -- Ukrainian military officials said Monday their troops have retaken another southeastern village from Russian forces, among the first -- small -- successes in stepped-up counteroffensive operations against Moscow's more than 15-month invasion of Ukraine.

Deputy Defence Minister Hanna Maliar wrote on Telegram that Ukraine's flag was again flying over the village of Storozhov, and she predicted the liberation of "all Ukrainian land" would be the final outcome. A day earlier, Ukrainian officials said three other small villages clustered together south of the town of Velika Novosilke in the eastern Donetsk region had been liberated.

The villages are located in the so-called "Vremivka ledge," a section of the front line where the Russian-controlled area protrudes into territory held by Ukraine. The area has become one of several epicentres of intense fighting.

The Russian Defence Ministry hasn't confirmed the Russian retreat from the villages, but some military bloggers have acknowledged the loss of Russian control over them.

Russian authorities, meanwhile, have said their troops have largely held their ground along the more than 1,000-kilometre (600-mile) arc of front line along southern and eastern Ukraine.

Western analysts and military officials have cautioned any effort to rid entrenched, powerfully armed and skilled Russian troops will likely take months, and the success of any Ukrainian counteroffensive is far from certain.

On Saturday, Ukrainian President Volodymyr Zelenskyy said "counteroffensive, defensive actions are taking place" without specifying it was an all-out counteroffensive, a day after Russian President Vladimir Putin asserted that the counteroffensive had started -- and Ukrainian forces were taking "significant losses." He did not elaborate, and Ukrainian authorities have not publicly specified losses among their troops.

The reported Ukrainian advance comes as authorities on both sides of the active front line along the Dnieper River in the southern Kherson region pressed on with rescue and relocation efforts for civilians driven from their homes by flooding from the breach of the Kakhovka dam last week.

The UN and other aid groups say access to fresh drinking water is a crucial need and the possible spread of water-borne disease a big worry.

On Sunday, a local official said three people were killed when Moscow's troops opened fire at a boat evacuating people from Russian-occupied areas.

Late Sunday, Zelenskyy said envoys from the International Criminal Court have visited the region to investigate the disaster, which has driven thousands from their homes, and left at least 14 people dead.

"It is very important that the representatives of international justice have seen the consequences of this Russian act of terrorism with their own eyes and heard for themselves that Russian terror continues," Zelenskyy said.

Ukrainian authorities have accused Russian forces, which controlled the area around the dam, of deliberately destroying it. Russian officials have blamed Ukrainian shelling for its destruction.