The latest upticks in violence are being watched around the world, with the United States and its NATO allies alleging that the Kremlin is looking for an excuse to invade Ukraine.
The Ukrainian military and their Moscow-backed separatist foes have traded allegations of fresh ceasefire breaches, escalating tensions amid fears of a Russian invasion.
The Ukrainian joint command centre for the eastern front said the rebels had violated the ceasefire 20 times between midnight and 9:00 am local on Friday (2200 to 0700 GMT).
The Donetsk and Lugansk separatist groups said the army had fired 27 times.
The latest upticks in violence involving artillery and mortar attacks are being watched around the world, with the United States and its NATO allies alleging that the Kremlin is looking for an excuse to invade Ukraine.
Russia, which has massed over 100,000 troops near Ukraine's borders, said on Thursday it was "deeply concerned" with the flare-up and was watching the situation closely.
Monitors from the Organization for Security and Co-operation in Europe (OSCE) reported 189 ceasefire violations in the eastern Donetsk region on Thursday, up from 24 the previous day.
It counted 402 ceasefire violations in the smaller neighbouring Lugansk region, up from 129 on Wednesday.
Russian-backed separatists control the eastern parts of both regions.
But the Ukrainian military said on Friday it has recorded 60 ceasefire violations by the pro-Russian separatists over the past 24 hours, with one soldier injured.
Separately, the military said late on Thursday they had no plans to launch an offensive on the rebels' positions.
A shell blast tore a hole in the wall of a kindergarten in the government-held eastern village of Stanytsia-Luganska on Thursday, sending international tensions soaring.
The 20 children and 18 staff inside escaped unharmed.
The European Union "strongly" condemned the attack, saying "indiscriminate shelling of civilian infrastructures is totally unacceptable..."
"As the European Union, we stand united in our unwavering support for Ukraine’s sovereignty and territorial integrity within its internationally recognized borders," EU Foreign Policy Chief Josep Borrell said in a statement on Thursday.
The conflict in Ukraine's east has rumbled on for eight years, claiming the lives of more than 14,000 people and forcing more than 1.5 million from their homes.