In Syria, U.S.-backed troops fighting ISIS in Raqqa have been accused of deploying munitions loaded with white phosphorus, an incendiary weapon whose use in populated civilian areas is banned under international law. Photos and video published by the local journalist group Raqqa Is Being Slaughtered Silently show what appears to be white phosphorous filling the air over Raqqa on Thursday night, amid the U.S.-backed offensive to retake the city from ISIS. White phosphorus munitions can burn human flesh down to the bone, and wounds contaminated by the chemical can reignite up to days later, poisoning victims and leading to organ failure or death. An unnamed U.S. official told The New York Times that the U.S.-backed forces fighting in Raqqa have access to white phosphorus munitions. The apparent use of white phosphorus came the same night as a U.S.-backed coalition airstrike reportedly hit an internet cafe in Raqqa, killing as many as 14 civilians. The Syrian Observatory for Human Rights says one of the civilians killed was an activist who was in the middle of sending a report to the monitoring group, when the airstrike destroyed the Al-Hason Net internet cafe.