On Monday, the Russian Defense Ministry said that militants had shelled a Russian military hospital killing a combat medic and injuring two others in Aleppo. One of the injured later also succumbed to her wounds, according to the ministry.

"Syria condemns in the most decisive fashion the shelling by terrorist groups of a Russian field hospital in Aleppo," the ministry said in a statement seen by RIA Novosti.

The attack came as Syrian military forces continue gains against foreign-backed terrorists in Aleppo, Syria’s second largest city which remains split between government forces in the west and terrorists in the east. 

The conflict in Syria, which flared up in March 2011, has claimed the lives of more than 400,000 people, according to an estimate by UN Special Envoy for Syria Staffan de Mistura.