New Delhi, March 2 : The Ukraine military says Russian paratroopers have landed in its besieged second-largest city Kharkiv, BBC reported. Russian troops have parachuted into Kharkiv stepping up an attack on Ukraine's second-largest city which saw dozens of civilian killings in bombings Tuesday. According to the Ukrainian military, the aerial assault began just as air raid sirens were starting to sound in Kharkiv and the surrounding region. The statement adds that the Russian troops attacked a regional military hospital, and that fighting is ongoing, BBC reported. Kharkiv has been the epicentre of much of the violence seen in Ukraine in recent days. On Tuesday, a missile struck the local government headquarters of Ukraine's second-largest city around 08.00 local time, sending a massive fireball into the sky and burning cars and nearby buildings. Another strike occurred later on Tuesday in one of Kharkiv's residential neighborhoods. Ukrainian President Zelensky later called the attack a war crime. At least 17 people were killed in Kharkiv on Tuesday, and dozens wounded, according to emergency officials. Some pundits have speculated that the artillery strikes on residential communities could be an effort by Russia to weaken the Ukrainian resolve to fight, BBC reported. The smaller southern city of Kherson has also fallen to Russian forces, local Ukrainian officials say. The frontline cities of Kharkiv, Sumy and Mariupol are still holding out against the Russian invasion. Meanwhile, the huge convoy of Russian armoured vehicles is now about 15 miles north-west of the capital Kyiv /IANS