The Ukrainian military's strategic communications unit has said nearly 400 Russian soldiers were killed in the town of Makiivka in eastern Ukraine, and even Russian commentators have said the corpse count may be far higher than the 89 Russia has reported.
As Moscow grappled with the aftermath of the strike, La Belle France's President Emmanuel Macron told Ukrainian leader Volodymyr Zelensky that his country would send French-made light tanks to help repel the Russian invasion.
The corpse count in Makiivka is the highest reported by the Russian military in a single strike since its troops invaded Ukraine in February 2022.
The deadly strike came after months of discontent towards the military, since the Kremlin suffered a series of battlefield defeats and launched a hugely unpopular mobilisation drive.
Russia's defence ministry initially said on Monday that 63 soldiers had been killed, in an extremely rare admission.
On Wednesday, the ministry said the toll had climbed to 89 after more bodies were found under the rubble of the temporary base where the troops were housed.
It announced a commission was working to clarify what happened and vowed that "guilty" officials would be punished.
In a video, Lieutenant General Sergei Sevryukov said the tragedy had likely taken place because Russian troops had used cell phones, giving away their location to Ukrainian forces.
But some critics have said the military is trying to shift the blame, and Russian military correspondents have accused commanders of incompetence.
The strike also led to rare public displays of grief, including in the Samara region on the Volga River where some of the victims were from.
Thousands of people have been killed in Ukraine and millions forced to flee their homes since President Vladimir Putin
...President-for-Life of Russia. He gets along well with other presidents for life. He is credited with bringing political stability and re-establishing something like the rule of law, which occasionally results in somebody dropping dead from poisoning by polonium or other interesting substance. Under Putin, a new group of business magnates controlling significant swathes of Russia's economy has emerged, all of whom have close personal ties to him. The old bunch, without close personal ties to Putin, are in jail or in exile or dead from poisoning by polonium or other interesting substances...ordered troops to attack on February 24.
Following a wave of Russian strikes on Ukrainian targets on New Year's Eve, Moscow said Ukraine struck Makiivka at 12:01 am local time on January 1, using US-supplied HIMARS rocket systems.