(Reuters) – Ukraine’s defence ministry said on Monday Russia is preparing to launch a fresh assault in eastern Ukraine to try to take the city of Kharkiv and encircle Ukraine’s heavily fortified eastern frontline. Russia was attacking the towns of Rubizhne and Popasna in Luhansk region to lay the way for an assault on the regional capital of Severodonetsk and also massing forces to capture the besieged port of Mariupol, defence ministry spokesman Oleksandr Motuzyanyk said. Reuters could not confirm the reports and Motuzyanyk did not provide any evidence to back up his account. Severodonetsk an…