A mortar shell fired by foreign-backed militants has struck an elementary school in the Syrian capital city of Damascus, leaving a female teacher dead and 23 students injured.

The Syrian TV reported that the shell hit the Thaqafi school in the Malki district of Damascus on Wednesday.

Meanwhile, the so-called Syrian Observatory for Human Rights confirmed the incident, adding that a teacher was killed in the mortar attack. The UK-based observatory added that some of the injured were in critical condition.

According to the official SANA news agency, the attack came on the first day of final exams for elementary and secondary schools in the Arab country.

Syria has been grappling with a deadly crisis since March 2011. The violence fueled by Takfiri groups has so far claimed the lives of over 222,000 people, according to reports.

Over 3.8 million Syrians have left their country since the beginning of the crisis. More than 7.2 million Syrians have also become internally displaced, according to the United Nations.

SSM/HSN/GHN