KYIV (AFP) - Ukraine said on Sunday (April 17) it was pausing the evacuation of civilians from the war-scarred east of the country for a day after failing to agree terms with Russian forces.

"As of this morning, April 17, we have not been able to agree with the occupiers on a ceasefire on the evacuation routes. That is why, unfortunately, we are not opening humanitarian corridors today," Ukrainian Deputy Prime Minister Iryna Vereshchuk wrote in a statement on social media, referring to Moscow's forces.

Ukrainian authorities have urged people in the eastern Donbass area to move west to escape a large-scale Russian offensive to capture its composite regions, Donetsk and Luhansk.

They have also recently accused Russian forces of targeting evacuation infrastructure, including busses and a train station in Kramatorsk where more than 50 people were reported killed in Russian strikes.

Ms Vereshchuk also urged Russian forces to allow for evacuations from the besieged and devastated port city of Mariupol, which Moscow's forces claim to have brought under their control.

"Once again, we demand the opening of a humanitarian corridor for the evacuation of civilians, especially women and children, from Mariupol," she wrote.

Ukraine President Volodymyr Zelensky said this week that if Russian forces kill Kyiv's troops remaining to defend the city, then a fledgling negotiation process to end nearly two months of fighting would be ended.