The General Staff of the Armed Forces of Ukraine said that north of the city of Sloviansk more than 10 settlements had come under fire, US broadcaster CNN reported.
Most civilians left the area weeks ago, CNN said.
The Russians continued to shell areas along the border of the Luhansk and Donetsk regions and were persisting with a ground assault to the east of the city of Lysychansk, which they took last month, according to the cnn.com website.
The Ukrainian military also said Russian troops used radio-electronic warfare means to suppress satellite communication channels, according to the ukrinform.net website.
Meanwhile, the UK Ministry of Defence said in an intelligence update on Monday that "Russia has used private military company Wagner to reinforce front-line forces and to mitigate manning shortfalls and casualties."
Monday is day 145 of Russia's war on Ukraine.
(gs)
Source: PAP, cnn.com, ukrinform.net