Russia said Ukraine shelled Russian military positions on Friday during a 36-hour ceasefire unilaterally declared by President Vladimir Putin, which Kyiv and its allies have dismissed as a sham.
The Russian defense ministry said that its positions had come under attack in the Luhansk, Donetsk and Zaporizhzhia regions, but that its troops were observing the ceasefire.
"Four mortar shells were fired at Russian positions by the Armed Forces of Ukraine in the direction of Lyman," it said.
Reuters could not immediately establish if there had been any lull in fighting. Kyiv has said it has no intention of halting fighting for the proposed Russian ceasefire, which Ukraine and its Western allies called a ploy designed to give Moscow time to reinforce troops and equipment.
Putin ordered a ceasefire in Ukraine over Orthodox Christmas, the Kremlin said on Thursday. Russian troops must hold fire for 36 hours from noon on January 6, the Kremlin said.
Many Orthodox Christians, including those living in Russia and Ukraine, celebrate Christmas on January 6-7.
Patriarch Kirill of Moscow, the head of the Russian Orthodox Church, called on Thursday for both sides of the war in Ukraine to observe a Christmas truce, a step dismissed by Kyiv as a cynical trap.
"Taking into account the appeal of His Holiness Patriarch Kirill, I instruct the Minister of Defense of the Russian Federation to introduce a ceasefire regime along the entire line of contact of the parties in Ukraine from noon on January 6, 2023 to midnight on January 7, 2023," Putin said in the order.
"Proceeding from the fact that a large number of citizens professing Orthodoxy live in the areas of hostilities, we call on the Ukrainian side to declare a ceasefire and allow them to attend services on Christmas Eve, as well as on Christmas Day," Putin said.
Ukraine earlier dismissed Kirill's appeal, though there was no immediate reaction to Putin's ceasefire announcement.
A senior aide to Ukrainian President Volodymyr Zelensky, Mykhailo Podolyak, cast the Russian Orthodox Church as a "war propagandist" that had incited the "mass murder" of Ukrainians and the militarisation of Russia.
"The statement of the Russian Orthodox Church about the 'Christmas Truce' is a cynical trap and an element of propaganda," he said.
Peace talks still halted
A senior Ukrainian official on Thursday reiterated Kyiv's rejection of any peace deal with Moscow that would allow Russia to keep Ukrainian territory seized by Russian forces.
Russian President Vladimir Putin told Turkish President Tayyip Erdogan earlier on Thursday that Moscow was open to dialog over Ukraine but that Kyiv would have to accept the loss of territories claimed by Russia, the Kremlin said.
"Axiom: why will it be impossible to make a deal with the Russian Federation?" Ukrainian presidential adviser Mykhailo Podolyak wrote on Twitter.
Axiom: why will it be impossible to make a deal with RF? RF (Putin) under the word "talks" offers & the world to recognize "its right to seize foreign territories" & "to fix the absence of legal consequences for mass killings on foreign territory".It's fully unacceptable.— Михайло Подоляк (@Podolyak_M) January 5, 2023
"The Russian Federation (Putin) under the word 'talks' offers Ukraine & the world to recognize 'its right to seize foreign territories' & 'to fix the absence of legal consequences for mass killings on foreign territory'. It's fully unacceptable."
Civilians killed by Russian shelling
A married couple and their 12-year-old son were killed when a Russian shell hit a residential building in southern Ukraine on Thursday, a presidential aide said.
Kyrylo Tymoshenko, deputy head of President Volodymyr Zelensky's office, said the building in the town of Beryslav in the Kherson region was hit as the family was preparing to celebrate the Orthodox Christian Christmas.
"People were preparing to celebrate Christmas together, but a cynical blow by the Russians killed them in their own home," Tymoshenko wrote on the Telegram messaging app.
He described the shelling as a base and mean attack that was carried out soon after Patriarch Kirill of Moscow, the head of the Russian Orthodox Church, called for a Christmas truce. Kyiv dismissed the appeal as a "cynical" trap.
Russia denies deliberately targeting civilians in what it calls its special military operation in Ukraine.