(CNN) Two chemical gas attacks have been reported in northern Syria, one in the region where a Russian helicopter was downed a day earlier, killing all five people on board. In the first alleged attack, cylinders suspected of containing chlorine gas were dropped in residential areas in the city of Saraqeb in Idlib province, the anti-regime, voluntary search-and-rescue group Idlib Civil Defence said in a post on its Facebook page. Russia, Syria's key military backer, has vehemently denied that a chemical attack took place. In a news release carried by Russian and Syrian state news agencies, Kremlin spokesman Dmitry Peskov said the claims of chlorine usage were fabricated by the media.Confidence growing among U.S. officials that incident in Saraqeb was a chemical attack, source saysSyrian government says five dead in Aleppo gas attackActivists say 30 people have breathing difficulties in alleged Idlib attack
The _ and Russian governments say three humanitarian corridors have been opened to allow for the distribution of badly needed food and medical aid to civilians and to provide residents -- along with rebels who choose to surrender -- the opportunity to leave.