"The phosphorous bombs were used against civilians in residential areas, which could create conditions for a humanitarian disaster," said Major General Viktor Poznikhir, the deputy commander of the chief operations branch of the Russian General Staff.
He said the ministry had evidence of the use of prohibited ammunition, including eyewitness and media reports, as well as injuries sustained in the attacks.
Russian chief surgeon Nikolai Yefimenko said incendiary weapons could cause cancer and other grave illnesses and had negative impact on the environment.
The use of incendiary weapons against civilian targets is prohibited since 1979 by Protocol III of the UN Convention on Conventional Weapons. Ukraine is a signatory to the protocol.