Russian forces have become "bogged down" trying to capture the Ukrainian border town of Vovchansk, Ukraine's top general Oleksandr Syrsky said Friday, though fighting on the eastern front remains intense.Kyiv has been trying to push back against a Russian ground assault in the northeastern Kharkiv region since May 10, when thousands of Russian troops punched through the border in a surprise attack.After initial success, "the enemy has got completely bogged down in street battles for Vovchansk and suffered very high losses in assault units," Syrsky said, but added that fighting near the eastern cities of Chasiv Yar, Pokrovsk and Kurakhove was "intense."Over 11,000 people have been evacuated from the Kharkiv region since Russia launched its new offensive, according to local governor Oleh Syniehubov.Syrsky's comments came as state-owned train operator Ukrainian Railways reported a flurry of strikes on the Kharkiv region's railway system, damaging tracks, train carriages and buildings."The enemy continues to make deliberate attempts to stop the railway in Kharkiv region," Ukrainian Railways said."At night, it struck civilian railway infrastructure again. The shelling damaged tracks, buildings, idle freight carriages and an electric train carriage," it added.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.