Bottles of Jameson Irish whiskey and a large gateau were delivered to a celebration at a top military aviation academy in Armavir.
The claims comes from a pro- Russian Telegram channel run by a former member of the Kremlin’s armed forces.
Pilots, including those participating in the war, were marking the 20th anniversary of their graduation from Armavir higher military aviation school. In all, 77 guests were at the event, many highly decorated and holding senior ranks.
But the party never got round to opening the whiskey and while the 20kg cake was cut, it was not eaten.
The channel, called Fighterbomber, reported: “By pure chance and thanks to the conscientiousness of the officers who put the anonymous cake and the booze aside, no one had time to eat the cake or taste the booze. It would have been a disaster. 77 guests. But everybody is alive. GUR [Ukrainian military intelligence] failed, and it’s good.”
The pro-war channel has 400,000 subscribers and is run by a former military pilot. It boasts close links to the air force.
It said academy staff found a CCTV image of the courier.
He was apparently tracked by Russia’s elaborate facial recognition databases as being from Melitopol in occupied Ukraine.
It said the man – identified only as 32-year-old E. Semenov – was detained at the local airport.
Fighterbomber said: “He immediately told everything – about the cake with a potent poison, which bottles were poisoned.”
A picture of the suspect was published by Russia’s Baza media outlet.
There has been no official comment from Russian law enforcement on the alleged poisoning bid.
Armavir is one of the country’s most prestigious aviation academies, founded by Stalin in 1940.
Meanwhile, Moscow officials said yesterday that more than half of the most severely injured Russian soldiers have lost limbs.
Alexei Vovchenko, a deputy labour minister, said 54% had at least one limb amputated. According to some current estimates, this could mean around 60,000 Russian troops have lost an arm or a leg during the war with Ukraine.
Britain’s Ministry of Defence said up to 190,000 Russian soldiers had been killed or been so badly injured they could no longer fight.
Analysts have suggested the ratio of severely injured to dead could be in the region of 1.7 to one.
Up to 50,000 Ukrainians, including civilians who have been injured by missiles, are estimated to have lost limbs since the start of the war. Kyiv does not provide casualty figures.
