Russian forces have become "bogged down" trying to capture the northeastern border town of Vovchansk, but were putting intense pressure on Ukraine's army in the east, Kyiv's top general said Friday.
Kyiv has been battling a fresh land assault on its northeastern Kharkiv region since May 10, when thousands of Russian troops stormed the border, making their biggest territorial advances in 18 months.
Despite initial success, "the enemy has got completely bogged down in street battles for Vovchansk and suffered very high losses in assault units," Ukrainian commander-in-chief Oleksandr Syrsky said on social media.
Vovchansk sits less than five kilometres (three miles) from Russia and has become an epicentre of fighting as Moscow seeks to create a "buffer zone" along the border to prevent future Ukrainian attacks.
In an attempt to seize the town, Russia "is currently moving reserves from different sectors to support active assault operations, but to no avail," Syrsky added.
He warned, however, that the situation was turbulent on the eastern front, where Russia claims its forces have made a string of gains in the past two weeks.
Fighting near the eastern towns of Chasiv Yar, Pokrovsk and Kurakhove has been particularly "intense", he said.
Russia said Thursday it had made inroads near the city of Bakhmut in Ukraine's eastern Donetsk region, and just three days before claimed to have seized the village of Bilogorivka, a key target for Moscow as it seeks to wrest control of the entire Lugansk region from Kyiv.
As Ukraine rushed troops to battle invading Russian forces in the northeast, Kyiv again accused Moscow of deliberately targeting civilians in strikes.
State-owned train operator Ukrainian Railways reported a flurry of attacks on the Kharkiv region's railway system overnight, damaging tracks, train carriages and buildings.
"The enemy continues to make deliberate attempts to stop the railway in Kharkiv region," it said on Telegram.
"At night, it struck civilian railway infrastructure again. The shelling damaged tracks, buildings, idle freight carriages and an electric train carriage."
The company shared photos showing smoke rising from a wrecked carriage, twisted metal and debris beside tracks and a depot with some blown-out windows.
Long-distance and suburban trains were running as scheduled, the state railway monopoly said, despite repeated Russian strikes on the network, which is vital for both civilians and the military.
Strikes on the city of Kharkiv, Ukraine's second-largest, killed at least seven people on Thursday, local authorities said.
Over 11,000 people in the wider region have been evacuated since Russia began its new offensive two weeks ago, according to local governor Oleg Synegubov.
Separately, Ukraine fired missiles overnight at the Russian-occupied Crimean peninsula, killing two "chance passers-by", the Russian-installed head of the region, Sergei Aksyonov, said.
