The British Defense Ministry said Saturday that Russia "highly likely" suffered more than 300 casualties in a New Year's Day strike on its troops in Ukraine at Makiivka near Donetsk City.
The ministry said it believes that "the majority were likely killed or missing, rather than wounded."
The ministry noted that while its Russian counterpart "took the rare step of publicly acknowledging" that it had suffered casualties, Russia claimed only 89 had been killed.
Latest Developments in Ukraine: Jan. 28
The British ministry said the Russian ministry "likely assessed" it could not avoid commenting on the strike because Russian commanders had come under widespread criticism following the incident.
The British ministry said in its intelligence update posted on Twitter that the difference between Russia's number of casualties and the likely true numbers "highlights the pervasive presence of disinformation in Russian public announcements."
The disinformation, the ministry said, is a result of a combination of deliberate lying authorized by senior leaders and "the communication of inaccurate reports by more junior officials, keen to downplay their failings in Russia's 'blame and sack' culture."
Ukraine said Russian missile strikes killed at least 10 Ukrainian civilians Friday as fierce fighting continued in the east of the country. Twenty others were wounded.
Ukrainian officials say most of the casualties from the missile strikes occurred in towns in the country's east and south that are near Russian artillery units. They follow Russian missile attacks that went farther into Ukrainian territory Thursday, killing 11 people.
Kyiv said its troops were involved in fierce fighting Friday with Russian troops in the eastern town of Vuhledar, part of the Donetsk region.
Ukrainian President Volodymyr Zelenskyy said in his nightly address Friday that fighting was heavy in Donetsk and that Russian forces were not just trying to achieve military gains but were also seeking to destroy towns and villages.
Earlier Friday, the European Union's top general said that Russia is taking the war in Ukraine into a "different stage," launching indiscriminate attacks against civilians and cities as a reaction to recent decisions by NATO allies to send advanced armaments to Ukraine in support of its war effort.
Speaking at a news conference in Tokyo, European External Action Service Secretary-General Stefano Sannino told reporters Russia is no longer focused on military targets but is making indiscriminate attacks on cities and people.
"I think that this latest development in terms of armed supply is just an evolution of the situation and of the way Russia started moving the war into a different stage," he said.
People check a destroyed house after a Russian rocket attack in Hlevakha, Kyiv region, Ukraine, Jan. 26, 2023.
"[Russian President Vladimir] Putin has moved from a concept of [a] special [military] operation to a concept now of a war against NATO and the West," Sannino said.
Russia has repeatedly denied targeting civilians in Ukraine.
Sannino's comments came as Germany and the United States announced this week they will send advanced battle tanks to Ukraine, hoping to match the firepower Russia has on the ground.
The EU general said the new supplies from the West are not an escalation but rather an effort to give Ukraine a chance to defend itself. He said the developments have forced Putin to change his initial narrative, in which he described the invasion as a "special operation" to free Ukraine from a Nazi regime.
"Now we are speaking about a war with NATO and the West. Different story," Sannino said.
Poland pledged Friday to send more tanks to Ukraine, promising an additional 60 tanks on top of 14 German-made Leopard 2 tanks it had already agreed to send.
Zelenskyy responded on Twitter, 'Thank you ... Poland for these important decisions to deliver to Ukraine 60 Polish tanks - 30 of which are the famous PT-91 Twardy, along with 14 Leopards."
Russian Foreign Affairs Ministry spokesperson Maria Zakharova said Friday the supply of Western tanks to Ukraine would not help Kyiv's military prospects but would rather "bring the countries of the West to a new level of confrontation with our country and our people."
On Thursday, Zelenskyy expressed gratitude for the growing number of countries pledging advanced weaponry, including tanks, while at the same time pressing the need to hasten delivery of the promised weapons systems.
Zelenskyy said the only way to stop "this Russian aggression" is with "adequate weapons." He emphasized, "The terrorist state will not understand anything else."
The Ukrainian president also credited Western supplies for added protection from Thursday's missile attacks. "Today, thanks to the air defense systems provided to Ukraine and the professionalism of our warriors, we managed to shoot down most of the Russian missiles and Shaheds," he said in his address.
"Unfortunately, it is difficult to provide 100% protection with air defense alone. Especially when terrorists use ballistic missiles," he added.
Some material in this report came from The Associated Press, Reuters and Agence France-Presse.