BEIRUT — A group monitoring the Syrian civil war said on Tuesday government forces had carried out a poison gas attack that killed six people in the northwest, and medics posted videos of children suffering what they said was suffocation. A Syrian military source described the report of an attack in the village of Sarmin in Idlib province as propaganda. “We confirm that we would not use this type of weapon, and we don't need to use it,” the source said. The Syrian government has previously denied accusations that it has used chemical weapons in the four-year-old war. The Syrian Observatory for Human Rights, which is based in Britain and tracks the conflict through a network of sources, said the six dead included a man, his wife and their three children. It cited medical sources as saying they died as a result of gas released from barrel bombs dropped on Monday evening and that the chemical used was likely chlorine. Dozens more people were wounded in the attack, the Observatory said. The Idlib branch of the Syrian Civil Defense rescue organization posted seven videos on YouTube, some at nighttime and some in a medical center. One video showed three children and a woman, all apparently unconscious, in a medical center. A voice off camera said the name of the village, Sarmin, and Monday's date. “One of the infants, only a few months old,” a male voice says, shaking, as he films a baby on a gurney with liquid around its mouth. Two more infants with limp bodies are brought in, one by a man wearing a gas mask and another carrying a young girl. “She's still alive doctor,” a man checking the girl says. “Doctor, doctor, she is still breathing.” The Syrian Civil Defense, also know as the “White Helmets” for the hard hats they wear, includes more than 2,000 humanitarian volunteers who work as first responders in a country where the medical infrastructure has broken down. It operates in insurgent-held areas of the country. — Reuters