CBS News cannot confirm the use of chemical weapons, but President Obama has said it would cross a "red line," reports CBS News correspondent Clarissa Ward.
According to activists in Syria, the attack took place in the village of Sarmin in Idlib Province, on the other side of the Turkish-Syrian border.
Videos uploaded by medics inside Syria appear to show the aftermath of a chlorine gas attack -- young children coughing and struggling to breathe. Activists inside the country say six people were killed including a man, his wife and their three children.
Over the past year, there have been multiple reports of the Assad regime using chlorine gas in these so-called barrel bombs -- crudely made bombs stuffed with explosives and shrapnel or chlorine and dropped onto civilian areas.