The chemical leaves deep skin burns and only stops combusting when deprived of oxygen, which generally results in victims being burned to the bone.

The U.S.-led coalition has dropped a white phosphorus bomb over Deir Ezzo, Syria — killing three civilians and injuring five — according to state news agency, SANA.

The bombing came a day after the U.S. military dropped another bomb over a village near the city of Hasakah that killed at least nine civilians, according to Press T.V.

Under Protocol III of the 1980 Convention on Conventional Weapons white phosphorous is banned for nations to use during air attacks in areas inhabited by civilians.

GlobalSecurity.org has said that the chemical leaves deep skin burns and only stops combusting when deprived of oxygen, which generally results in victims being burned to the bone. The chemical can also stick to clothing or remain in buildings and infrastructure putting others at risk of coming into contact with the substance even after it has been ignited.

In August, Syrian Ministry of Foreign Affairs and Expatriates wrote to the U.N. Secretary-General Antonio Guterres and rotating President of the U.N. Security Council Amr Abdellatif Aboulatta saying that the U.S. has continually committed crimes against humanity in bombing civilian neighborhoods in Syria since it started air strikes there in September 2014.