The head of Russia’s Wagner private army has said it is not getting the ammunition it needs from Moscow, as it seeks to gain control of Bakhmut.
Russian troops – from Wagner and regular Russian forces – are trying to seize the eastern city from Ukraine.
But Wagner boss Yevgeny Prigozhin has complained of a lack of ammunition, saying it could be “ordinary bureaucracy or a betrayal”.
Relations between Wagner and Moscow seem increasingly tense.
The Wagner group has tens of thousands of troops in Ukraine – some recruited directly from Russian prisons – and has become a key part of Moscow’s invasion.
In a post on Sunday, Mr Prigozhin said documents had been signed on 22 February, with ammunition expected to be sent to Bakhmut the next day.
But most had not been shipped, he said, before suggesting it could be deliberate.
Separately, in a video uploaded on Saturday – but seemingly filmed in February – Mr Prigozhin said his men feared that they were being “set up” as scapegoats in case Russia lost its war in Ukraine.
“If we step back, we will go down in history as the people who took the main step to lose the war,” he said.
“And this is precisely the problem with the shell hunger [ammunition shortage]. This is not my opinion, but that of ordinary fighters…
“What if they [the Russian authorities] want to set us up, saying that we are scoundrels – and that’s why they are not giving us ammunition, not giving us weapons, and not letting us replenish our personnel, including [recruiting] prisoners?”
In Saturday’s video, Mr Prigozhin said Russia’s front line would collapse without his troops.
“If Wagner PMC [private military company] were to now retreat from Bakhmut, then the entire front – which PMC Wagner today is cementing – would crumble.”
He suggested Wagner fighters were taking on the “entire Ukrainian army … destroying it” and depriving it of the chance to concentrate on other parts of the front.
While the private army was “moving forward”, the Russian military was being forced to “catch up in order to save face”, he implied.
Last month, Mr Prigozhin complained that Defence Minister Sergei Shoigu and Chief of the General Staff Valery Gerasimov were withholding supplies of munitions to his troops.
Ukraine’s troops were probably conducting a “limited fighting withdrawal” in eastern Bakhmut, the Institute for the Study of War (ISW) said on Monday.
But it added Ukraine was “continuing to inflict high casualties” on Russian forces.
The ISW said the Russian military relied on Wagner in the months-long effort to seize Bakhmut and had since “reinforced Wagner forces in Bakhmut with Russian airborne elements and mobilized personnel”.
On Saturday, the deputy mayor of Bakhmut told the BBC that there was street fighting between Russian and Ukrainian forces.
However Oleksandr Marchenko said Russian troops had not yet gained control.
“They have no goal to save the city… their only goal is killing people and the genocide of the Ukrainian people,” Mr Marchenko told the Today programme.
Meanwhile, Ukrainian military officials said leaders of Russia’s 155th Brigade fighting near the town of Vuhledar, south of Bakhmut, had resisted orders to attack after sustaining severe losses.
The Russian Defence Ministry said its forces had hit a command centre of the Ukrainian Azov Regiment in southeastern Zaporizhzhia region.
Separately, Moscow’s Defence Minister Sergei Shoigu has visited the occupied city of Mariupol during a trip to eastern Ukraine – a year after his troops besieged the city.
The defence ministry said he was inspecting work carried out to “restore infrastructure in the Donbas” – words that are likely to grate in Ukraine, given Russia’s responsibility for the destruction.