Ukrainians have killed Russian soldiers by poisoning food and alcohol, according to the country's intelligence services.
Civilians in Izyum near Kharkiv have been fighting back against the Russians, who have destroyed great tracts of the city with relentless shell attacks.
Locals baked cakes for the 3rd Russian Motor Rifle division, lacing them with poison, the Ukraine Defence Intelligence Directorate claimed.
"As a result, two invaders were killed at once, another 28 went to intensive care. Their current state is to be specified," the organisation announced.
A further 500 soldiers from the 3 Motostrils Division are in hospital with "heavy alcohol poisoning of unknown origin", it was claimed.
Despite their efforts, Ukrainian civilians have been unable to stop the Russians destroying their towns and cities.
The suburbs of Izyum, a city of 50,000, have been flattened by both indiscriminate shelling and precision strikes.
Schools have been destroyed, health clinics reduced to rubble by shelling and ordinary houses demolished by airborne assaults.
Mykola Shaposhnyk, who lived in a village called Hrushuvakha, told Sky News: "The planes fly low. They were bombing so slowly, not in a rush, not in a rush.
"He is erasing the population, maybe to try and make people leave the place. Destroying Ukraine, definitely.
"Even my father, who lived through the (second world) war, said the Germans didn't do this."
According to Valerii Marchenko, the city's mayor, roughly 20,000 people are currently stuck in Izyum.
Many are hiding in air raid shelters, slowly running out of food and medicine.
The decision of the invading forces to abandon efforts to take Kyiv and focus on the east of the country was seen as a sign of the strength of the Ukrainian resistance effort.
Yet the grim reality is that the evacuating Russians are leaving a trial of misery and destruction behind them.
The mayor of the liberated town of Bucha said 300 residents had been killed during a month-long occupation by the Russian army, and victims were seen in a mass grave and still lying on the streets.
Reuters journalists saw bodies lying in the streets and the hands and feet of multiple corpses poking out of a still-open grave at a church ground.
"The bastards!" Vasily, a 66-year-old man said, weeping with rage as he looked at more than a dozen bodies lying in the road outside his house.
"I'm sorry. The tank behind me was shooting. Dogs!"
After more than five weeks of fighting, Russia has pulled back forces that had threatened Kyiv from the north to regroup for battles in eastern Ukraine.
"The whole Kyiv region is liberated from the invader," Ukrainian Deputy Defence Minister Hanna Malyar wrote on Facebook on Saturday.
President Volodymyr Zelenskiy warned in a video address: "They are mining all this territory. Houses are mined, equipment is mined, even the bodies of dead people."
Ukraine's emergencies service said more than 1,500 explosives had been found in one day during a search of the village of Dmytrivka, west of the capital.
Russia has depicted its drawdown of forces near Kyiv as a goodwill gesture in peace talks. Ukraine and its allies say Russia was forced to shift its focus to east Ukraine after suffering heavy losses.
Both sides described talks last week in Istanbul and by video link as "difficult".
