Local sources confirm "Russian military planes launched two missiles that completely destroyed a Medecins Sans Frontieres hospital near the town of al-Hamidiya on the outskirts of Idlib."
"The Russian airstrikes killed four civilians including a child. Local medics are looking for the scores of injured buried under the rubble," they added.
International humanitarian organisation, Medecins Sans Frontieres have confirmed the incident in a tweet posted on their social media account.
Russia began a bombing campaign in September last year to back up those fighting for its longstanding ally Assad. Last year its pilots carried out more than 5,000 sorties.
Syrian opposition groups have accused Moscow of mainly targeting moderate rebels fighting the Assad regime as well as inflicting civilian casualties, a view shared by Western governments too. Moscow insists it is tackling "terrorist" groups such as the Islamic state [IS] group.