Ukraine said Monday it had foiled 55 Russian attacks in the eastern Donetsk region, a day after it admitted to a worsening situation on the front line.
Moscow over the weekend claimed another eastern village, Novobakhmutivka, as struggling Ukrainian forces await the arrival of crucial US weapons.
The Ukrainian army said it had "repulsed 55 attacks" in several villages north and west of Novobakhmutivka.
These included Ocheretyne, where heavy fighting was reported on Sunday.
The villages lie north of the hub of Adviivka, captured by Russian troops in February. Moscow's forces have since pushed deeper into the Donetsk region.
Further south, Ukraine said its forces "continue to hold back the enemy" in several settlements west of the Moscow-held city of Donetsk, including the town of Krasnogorivka.
Kyiv said Russian forces had "with the support of aviation, tried 15 times to break through the defences of our troops."
Krasnogorivka lies some 20 kilometres (32 miles) west of Donetsk and has served as a key stronghold for Kyiv.
It has become more vulnerable since the fall of nearby Marinka and Avdiivka, with reports of increased fighting in recent weeks.
Ukraine's commander-in-chief Oleksandr Syrsky said Sunday his troops had retreated to new defensive lines further to the west in some areas.
Kyiv has also warned Russia will try to bring home some victories ahead of its patriotic May 9 holiday.