At least 15 people were killed Tuesday in northern Aleppo province of Syria when armed men fired a rocket stuffed with chemical materials, the state-media said.

The state media didn't elaborate on the report but it was the first time that Syria accuses the western-backed rebels of using chemical weapons.

Meanwhile, other media report cited medical sources in the area as reporting the death of 15 people and the injury of dozens of others, saying that hospitals have received cases with suffocation and toxicity due to exposure to unknown gases believed to be loaded on rockets' head.

Khan al-Asal town, southwestern outskirts of northern Aleppo province, has been a scene of intense fighting between the government troops and rebel fighters due to its strategic importance.

The rebels stormed the town and had taken control over a police academy before the Syrian troops waged a wide-scale offensive and recaptured the area last week, according to local media.

The file of chemical weapons in Syria has emerged lately with western and Israeli officials expressing fears that the country's chemical weapons may fall in the "wrong hands," in reference to the radical rebels affiliated with al-Qaida who are fighting in Syria under the title of Nusra Front.