Russian President Vladimir Putin has sent a 15,000-strong army corps to southern Ukraine to blunt Kyiv’s counteroffensive, western officials have said.
With Ukrainian troops advancing on Kherson, the first urban area to be captured by Russia, Mr Putin is understood to be desperate to hold on to it.
It has been reported that the Russians have resorted to ferrying troops and supplies into the city on a makeshift pontoon bridge after the last road crossing over the Dnipro River was disabled by long-range missile strikes.
But western officials have now confirmed reports that the Russians have built a new force, many taken from domestic prisons, that could be used in an offensive potentially starting next month.
“We can confirm that we are seeing a formation,” a western official briefed. “An army corps is typically 10,000 to 15,000 personnel but we're not sure how it will be employed.
“We can't even comment on whether it's going to be employed in Ukraine or not. But there is a range of options open to the Russians — reinforcing Kherson or a counterstrike in the southern region.”
Ukrainian officials have said the military build-up is occurring close to the steel-producing city of Kryvyi Rih — where President Volodymyr Zelenskyy grew up — about 50 kilometres from the current southern front line.
“It’s quite likely the enemy is preparing a hostile counteroffensive with the subsequent plan of getting to the administrative boundary of Kherson region,” Ukrainian military commanders said on Thursday.
Western intelligence officials rejected Russian media reports that an alleged attack on a prisoner-of-war jail that killed 53 Ukrainians last month was caused by one of Kyiv’s long-range missiles.
“Looking at the photos, which have been released by the Russians of the site, it's clear to our explosive experts that this wasn't a high explosive strike from the outside,” a western official said.
“It's much more likely to be incendiary and from within inside. What is important here is if you look at things like bunk beds, they are still standing. That just would not be the case if there had been a high attack from a Himars [long-range missile].”
UN Secretary General Antonio Guterres said he is launching a fact-finding mission to investigate killings in the separatist region of eastern Ukraine.
US intelligence officials have said that Russia has planted false evidence at the site.
It was also reported that a second ship will head into the Black Sea on Wednesday carrying 41,000 tonnes of grain destined for the UK.
The Rojen will reportedly dock in Teesside on about August 14 August as part of the Black Sea Grain Initiative, a deal struck between Ukraine and Russia last week and overseen by Turkey, that Kyiv hopes will help export a 20 million-tonne grain mountain stuck in the country's silos since the war started.
Grain shipments will also will help alleviate the food crisis in the Middle East and North Africa.
Western officials indicated that there would be no Nato or other warships sent to the Black Sea as the accord was entirely built on consensus.
