Ukrainian troops advanced further into the northeastern region of the country on Tuesday, reclaiming the town of Vovchansk, 3 kilometers from the Russian border, that Moscow's forces had seized on the first day of their invasion nearly seven months ago.
The Kyiv government exulted in its sudden success, with President Volodymyr Zelenskyy saying late Monday that in the last few weeks its forces had retaken more than 6,000 square kilometers.
"The movement of our troops continues," he said.
Ukrainian troops hoisted the country's blue-and-yellow flags and officials released video of soldiers burning Russian flags and inspecting the charred tanks Russian troops left behind as they retreated. Border guards tore down a poster that read, "We are one people with Russia."
U.S. officials Tuesday confirmed the Russian retreat.
"I think what you're seeing is a shift in momentum," National Security Council coordinator John Kirby told reporters at the White House.
"In the north, we have seen Russians evacuate, withdraw, retreat from their defensive positions, particularly there in and around the Kharkiv oblast," he said. "They have left fighting positions. They have left supplies."
But Kirby also sounded a note of caution.
"These are some dramatic events we're watching but it's war and war is unpredictable," he said. "It remains to be seen what [Russia's] next steps are going to be here as the Ukrainians remain on the offense up in the north and continue to pursue a counteroffensive down in the south."
Pentagon officials on Tuesday likewise confirmed some Russian forces in and around Kharkiv had slipped back across the border into Russia, though they said that should not be seen as a sign Moscow is backing down.
"Clearly they've demonstrated their intent to keep fighting," Pentagon press secretary, Brigadier General Patrick Ryder, told reporters. "Russian forces do exist en masse in Ukraine."
Top Ukrainian officials in recent days have warned Russia may turn to a new wave of cyberattacks, targeting Ukraine's energy and financial sectors, as its military campaign gets bogged down.
U.S. officials have also noted recent Russian airstrikes have targeted Ukrainian power generation stations, causing blackouts across Ukraine.
Ukrainian Deputy Minister Hanna Maliar said Kyiv is trying to persuade Russian soldiers to surrender, firing shells filled with flyers ahead of their advance.
"Russians use you as cannon fodder. Your life doesn't mean anything for them. You don't need this war. Surrender to Armed Forces of Ukraine," the flyers read.
In its latest assessment, British intelligence said that one of Russia's premier forces, the 1st Guards Tank Army, had been "severely degraded" during the war with Ukraine and that "Russia's conventional force designed to counter NATO is severely weakened. It will likely take years for Russia to rebuild this capability."
With the Ukrainian advances, German Chancellor Olaf Scholz urged Russian President Vladimir Putin in a telephone call to "come to a diplomatic solution as quickly as possible, based on a cease-fire, a complete withdrawal of Russian forces and respect for the territorial integrity and sovereignty of the Ukraine," according to the chancellor's spokesman.
"Russia needs to understand that the international community stands behind Ukraine, that Russia can't count somehow on holding out and waiting until the international community weakens," a senior U.S. defense official said Monday, speaking on the condition of anonymity under ground rules established by the Pentagon.
The official also said it was apparent that "really enormous miscalculations" by Russia about its own forces as well as about the ability of the Ukrainian military were beginning to impact the Russian invasion.
Analysts say the war is likely to continue into 2023, but the Washington-based Institute for the Study of War said Monday that "Ukraine has turned the tide of this war in its favor" through its effective use of Western-supplied weapons like the long-range HIMARS missile system and strategic battlefield maneuvers.
"Kyiv will likely increasingly dictate the location and nature of the major fighting."
Russia continued to shell Ukrainian positions, including the city of Lozova in the Kharkiv region, where three people were killed and nine injured, according to Ukrainian regional governor Oleh Syniehubov.
Fighting also raged near the Zaporizhzhia nuclear power plant, where officials remain worried about the safety of the facility and fears of radiation leaks.
Some information in this report came from The Associated Press.