A Syrian teacher was killed and 23 students were wounded when a mortar shell hit their school on Wednesday in the heart of Damascus, Syrian state media said.

State media said "terrorists" had carried out the attack, a term it uses to describe insurgents.

Earlier this year the capital came under heavy bombardments from Islam Army insurgents based in the outskirts of Damascus, at least 17 people were killed in the campaign.

No group has so far claimed responsibility for the attack.

Damascus has largely been shielded from the war which has killed more than 220,000 since a revolt against President Bashar al-Assad erupted in 2011.

Two years ago, insurgents including Islamist groups posed a serious threat to the capital when they took some of its neighbourhoods. The army pushed them back to the countryside two years ago after launching a major offensive.