The Syrian government has allegedly launched two chemical gas attacks in northern Syria, killing an entire family.

According to human rights watchdog Amnesty International, the Syrian government allegedly dropped barrels of chlorine gas on the towns of Sermine and Qmainass on March 16. Eyewitnesses told the group that the barrels were dropped from four government helicopters.

Civil defence members rushed to the site to assist. According to Amnesty International, the responders found symptoms characteristic of gas attacks including "reddened eyes, shortness of breath, continuous coughing, respiratory distress, vomiting, and drooling from the mouth."

One civil defence operative told Amnesty International of how they attempted to rescue a family from the basement of a house. He said that civil defence members who had masks rushed down to the basement of a building after being told that an entire family was living there.

"I saw a woman on the stairs. She was blue and was not breathing," the operative, who spoke anonymously, told the human rights group. He said that he was not able to proceed because he was not wearing a mask, but other civil defence members with face masks went to the basement in an attempt to rescue the other members of the woman's family.

"They evacuated the father, mother and three babies. They all died," he concluded.

Amnesty International's Middle East and North Africa Programme Director Philip Luther condemned the attack, describing it as a war crime. He called on the International Criminal Court to pursue legal action against Syrian President Bashar al-Assad's regime.

"The situation in Syria must be referred to the International Criminal Court as a matter of urgency," Luther urged.

 Syria's military denied responsibility for the attack, which also injured members of the Free Syrian Army.

President al-Assad had pledged in September 2013 to eliminate Syria's stockpile of prohibited chemicals after a deadly sarin gas attack that killed hundreds outside Damascus. However, the Organisation for the Prohibition of Chemical Weapons published a report in September last year detailing evidence that the Syrian government continues to systematically use chemical weapons in northern Syria.