A video recently posted to the Internet depicting an improvised explosive device (IED) attack in Syria has garnered a great deal of attention. A Syrian militant group called the Hawks Brigade of the Levant claimed the attack, which targeted a Syrian government armored troop bus as it traveled along a road near a rebel stronghold in the Idlib governorate. According to the group, the attack depicted in the video employed a type of IED called an explosively formed penetrator (EFP). Though the video was shot from a fairly long distance away, it does appear that the IED punched a substantial and focused hole through the armored bus -- precisely the type of effect that would be expected if an EFP were employed against such a target.
EFPs are a logical tool for militants to use against superior government forces that are heavily dependent upon armor. EFPs pose a significant threat to armored vehicles, which the Syrian military has utilized extensively, and quite effectively, in its campaign against Syrian rebel groups.
Studying the IED technology employed by a militant group is an important way to determine the group's logistics situation and trajectory. It can also be a way to discern if a group is receiving outside training and logistical assistance.
Explosively Formed Penetrators
An explosively formed penetrator, sometimes called an explosively formed projectile, is a simple device composed of a case, a liner and explosive filler. EFPs have been part of many countries' military inventories for years. The U.S. Army, for example, added the M2 Selectable Lightweight Attack Munition (aptly named the SLAM) to its inventory in 1990. Improvised EFP devices can also be constructed by non-state actors; they were widely used to target U.S. military vehicles in Iraq.
The employment of an EFP device in the field also requires a detonator and a firing chain to initiate the detonator. The firing chain can vary widely, from a hardwired command-detonated system to an improvised victim-actuated system that is triggered inadvertently by the target and involves modifying things like the infrared safety beam from a garage door opener.