Moscow has not officially commented on the alleged mutilation.
The head of the Luhansk Oblast Military Administration said the decaying bodies are now seeping into the region's drinking water, leading people who drink water from the wells to develop an infection.
One woman was wounded as a result of the attack, according to Ukrainian officials.
The disguised Russian soldiers reportedly wore the field uniform of the Ukrainian army when they attacked in the Avdiivka direction.
Phosphorus bombs can cause deep burns on victims and can even burn through bone.
The "performance" is aimed at Russian citizens in order to reduce the dissatisfaction with the war among the local population, according to Ukrainian intelligence.
The SSU destroyed three Russian T-72s, battle tanks commonly used by the Soviet Union in the 1970s.
Consuming contaminated drinking water can cause dysentery and cholera.
The boy will have to undergo several difficult operations in Germany, according to a report.
The incident allegedly occurred between the occupied Ukrainian cities of Melitopol and Berdiansk.
Melitopol was one of the first Ukrainian cities to fall within a week of Russia's invasion.
Kyrgyz citizens are being recruited under the guise of recruiting workers to protect "industrial facilities in remote regions of Russia," a report said.
The Ukrainian army has now killed more than 39,500 Russian soldiers since the war began in February.
The partially Russian-occupied Donetsk region of Ukraine had the most number of children affected by the war.
Russian private military companies reportedly began recruiting Belarusian fighters this month.
A Russian soldier told his parent that a comrade from the same unit was dismissed from service after breaking his leg.
A Russian soldier also complained about being paid only half of the salary he was promised upon signing the contract.
The miner enlisted in the Russian army at the start of the invasion in February.
A spokesman for one of the Chechen volunteer battalions said they are preparing to fight against Moscow to once again gain independence from Russia.
More than 38,500 Russian soldiers have now been killed in the war in Ukraine.
Two Russian lawmakers claimed Ukrainian soldiers were given performance enhancing drugs to turn them into 'cruel murder machines.'
The Russian conscripts were initially told they would be taken to the airport.