Ukrainian forces made further gains Monday in the Kherson region in the country's south, adding to their gains in the east in recent days as they push a counteroffensive against Russia to recapture lands Moscow's forces had claimed earlier in its seven-month invasion.
Russia-installed officials in Kherson said Ukraine's military had recaptured some settlements, while the Russian Defense Ministry acknowledged that "with superior tank units," Ukraine had "managed to penetrate into the depths of our defense."
Ukrainian President Volodymyr Zelenskyy said in his nightly address Monday that Ukraine's military was moving ahead with its advances. Without providing details, he said the army had seized back towns in several areas
"New population centers have been liberated in several regions. Heavy fighting is going on on several sectors of the front," he said.
Zelenskyy said Sunday that his forces in Kherson had liberated the settlements of Arkhanhelske and Myroliubivka.
Still, a Russian defense spokesman said Moscow's troops "have occupied a pre-prepared defensive line and continue to inflict massive fire damage" on Kyiv's forces. Kherson is one of four regions that Russian President Vladimir Putin illegally annexed last week.
A senior U.S. military official said Monday that the U.S. sees heavy fighting continuing as Russian forces try to push west, "but no significant shifts on the ground have occurred as Ukrainian forces continue to hold the line."
In Moscow, Russia's lower house of parliament quickly rubber-stamped an endorsement of the treaties for four regions of Ukraine to join Russia, which the upper house is set to do on Tuesday.
But the boundaries of the Russian annexation were not precisely clear. Kremlin spokesman Dmitry Peskov said two regions, Donetsk and Luhansk, are joining Russia with the same administrative borders that existed before fighting erupted in 2014 between pro-Russian separatists and Ukrainian forces.
But Peskov said the borders of the two other regions — Zaporizhzhia and Kherson — remain unsettled. "We will continue to discuss that with residents of those regions," Peskov told reporters, without elaborating.
The developments in Kherson followed Sunday's announcement by Ukrainian forces that they had retaken full control of Lyman, the eastern logistics hub that is also within territory that Russia claimed last week was its own.
"Lyman is fully cleared," Zelenskyy declared in a short video clip on his Telegram channel.
Russia did not comment Sunday on the fate of Lyman but said Saturday that its troops were retreating from the area because it feared Ukrainian forces were about to encircle them. Russia captured Lyman in May and had used it as a logistics and transportation hub for its operations in the north of the Donetsk region.
Russia's loss of Lyman was its biggest battlefield defeat since Ukrainian forces last month swept through the Kharkiv region in northeastern Ukraine, pushing Russian forces back toward their border.
In addition to claiming the annexations rejected by Ukraine and its Western allies, Putin late last month ordered the mobilization of 300,000 reservists to bolster Russia's forces.
The order sparked protests in some areas of Russia and long lines at borders as tens of thousands of would-be conscripts have fled to other countries.
The governor of Russia's Khabarovsk region said Monday that the military commissar in the region was removed from his post after half of the personnel who were mobilized did not meet draft criteria and were sent home.
The governor said in a Telegram video that the commissar's removal would not affect the overall mobilization plan. .
Carla Babb contributed to this report. Some information for this story came from The Associated Press, Agence France-Presse and Reuters.