ReutersUkraine and Russia have accused each other of breaching a 30-hour "Easter truce" that was announced by the Russian president on Saturday.
Ukrainian President Volodymyr Zelensky claimed Ukraine's front line had been hit by more than 46 Russian assaults since the start of the day on Sunday. The BBC has not independently verified these figures.
In response, Russia's defence ministry said it had "repelled" attempted assaults by Ukraine and accused Kyiv of launching hundreds of drones and shells, according to state media sources.
On Saturday, Putin said there would be an end to all hostilities from 16:00 BST on Saturday until 22:00 BST (midnight in Moscow) on Sunday. Kyiv said it would also adhere.
"For this period, I order all military actions to cease," Putin said in his announcement.
"We assume that the Ukrainian side will follow our example. At the same time, our troops must be ready to repel possible violations of the truce and provocations from the enemy, any of its aggressive actions."
However, Zelensky said Ukraine saw hundreds of attacks and drone launches on Sunday and that Putin's declaration of a truce amounted to a "PR" exercise.
Zelensky added that Vladimir Putin's words were "empty" and he accused the Kremlin of trying to create "a general impression of a ceasefire".
"This Easter has clearly demonstrated that the only source of this war, and the reason it drags on, is Russia," the president said on Sunday.
The Russian defence ministry insisted its troops had "strictly observed the ceasefire".
The surprise "Easter truce" announcement came shortly after US President Donald Trump threatened to "take a pass" on brokering further Russia-Ukraine peace talks.
Ukraine had said it would be ready to extend the truce, which is due to come to an end at midnight local time tonight (22:00 BST).
There were mixed reactions about the 30-hour truce from Ukrainians attending Easter morning services in Kyiv and the Russian-occupied city of Donetsk on Sunday.
"I do not think this man [Putin] has anything to do with humanity," 45-year-old lawyer Olena Poprych told Reuters news agency.
Meanwhile in Donetsk, where much of the city has been under Russian control since 2014, residents expressed similar distrust that Zelensky will stick to the terms of the ceasefire.
"I watched very closely his [Zelensky's] reactions," said Vladimir, who attended an Easter morning service in Donetsk. "There was nothing about the ceasefire... just some vague statements, not giving any confidence that we will not be shelled."
Russia launched a full-scale invasion of Ukraine on 24 February 2022. It is estimated that hundreds of thousands of people - the vast majority of them soldiers - have been killed or injured on all sides.
The US has been directly talking to Russia as part of its efforts to end the war, but has struggled to make major progress.
Last month, Moscow came up with a long list of conditions in response to a full and unconditional ceasefire that had been agreed by the US and Ukraine.
On Friday, Secretary of State Marco Rubio said the US was not "going to continue with this endeavour for weeks and months on end", as it had "other priorities to focus on".
"We need to determine very quickly now - and I'm talking about a matter of days - whether or not this is doable," he added.
"If it's not going to happen, then we're just going to move on."
