Air strikes killed at least 18 people and wounded dozens in the northwestern Syrian province of Idlib on Tuesday, the Syrian Observatory for Human rights said.
Syrian government or Russian jets pounded the town of Khan Sheikhoun in rebel-held Idib in the morning, the Britain-based war monitoring group said.
The strikes caused many people to choke, the Observatory added, citing medical sources who described it as a gas attack.
The Syrian government has repeatedly denied using any such weapons.
Source: Reuters