Ukraine's Zelenskiy: Heavy Russian losses in the east

Ukraine's President Zelenskiy speaks during a joint news conference with Czech Prime Minister Fiala in Kyiv

(Reuters) - Russia is suffering heavy losses in continuing "fierce" attacks in Ukraine's eastern Donetsk region and is preparing new assaults on Ukrainian energy infrastructure, Ukrainian President Volodymyr Zelenskiy said on Sunday.

"Very fierce Russian attacks on Donetsk region are continuing. The enemy is suffering serious losses there," Zelenskiy said in his nightly video address.

Zelenskiy said he believed Russia was "concentrating forces and means for a possible repetition of mass attacks on our infrastructure, energy in the first instance".

(Reporting by Ron Popeski and Elaine Monaghan; Editing by Daniel Wallis)