The total length of the tunnel was about 200 meters (0.12 miles), while the explosive device was placed directly underneath the church building. Tens of civilians could have been injured in case of a blast.
The situation in Aleppo has been deteriorating steadily over the recent months. Thousands of citizens are believed to be trapped in the terrorist-besieged eastern parts of Aleppo with no access to food or water. There have been several attempts to establish a ceasefire, however the bids have failed.
On Tuesday, the Russian Defense Ministry said that Syrian government forces had cleared almost half of Aleppo from militant strongholds, liberating some 80,000 residents.
The Syrian civil war is ongoing since March 2011, with different countries, regional powers and terrorist organizations such as Daesh and Jabhat Fatah al-Sham (previously known as al-Nusra Front), both outlawed in Russia, involved in the conflict.