By Nathan Morley
According to the testimony of several medical workers, a bomb filled with chlorine was dropped by a government helicopter in Saraqeb, a small rebel held town near Idlib.
The Syria Civil Defence unit – known as the ‘White Helmets’ say three of their employees were left injured in the attack and nine others are being treated for severe breathing problems.
Chlorine bombs, which burst on impact, have been used on countless occasions during the war in Syria. Those exposed to chlorine can be left choking, foaming at the mouth or suffer violent coughing fits, with children and pensioners especially vulnerable.
Elsewhere in Syria, more reports of violence are emerging.
At least twenty deaths have been reported after Russian and government air-strikes in several locations across Idlib. The United Nations estimates that 2.5 million people live in the area, including around a million refugees displaced by fighting from other parts of the country.
Over the weekend rebels shot down a Russian jetfighter over the province and killed its pilot on the ground after he ejected.
Elsewhere, two people have been killed after shelling near a Russian aid distribution point in the capital, Damascus, according to the Russian RIA wire-service.
In a separate development, the Iranian Foreign Ministry has urged Turkey to stop the military operations against the Kurdish militants entering Syria's Afrin, saying Ankara should protect the territorial integrity of Syria and respect the national sovereignty of the Arab state.