Al Qaeda - backed Nusra Front group carried out the bombings west of Aleppo . The detonated explosives buried in a tunnel beneath an intelligence HQ . 20 Syrian regime security soldiers were killed along with dozens of the militants . Blast was so huge that many experts mistook it for a small earthquake . the international Seismological Centre estimated the blast measured a magnitude of 2.3 on the Richter scale .
Al Qaeda-backed Nusra Front group carried out the attack west of Aleppo . The detonated explosives buried in a tunnel beneath an intelligence HQ . 20 Syrian regime security soldiers were killed along with 14 of the terrorists . Blast was so huge that many experts mistook it for a small earthquake . European Mediterranean Seismological Centre said the blast measured a magnitude of 2.3 on the Richter scale .