An improvised explosive device (IED) is a homemade bomb constructed and deployed in ways other than in conventional military action. It may be constructed of conventional military explosives, such as an artillery round, attached to a detonating mechanism. Roadside bombs are a common use of IEDs.
IEDs may be used in terrorist actions or in unconventional warfare by guerrillas or commando forces in a theater of operations. In the second Iraq War, IEDs were used extensively against US-led Coalition forces and by the end of 2007 they had become responsible for approximately 63% of Coalition deaths in Iraq. They are also used in Afghanistan by insurgent groups, and have caused over 66% of the Coalition casualties in the 2001–present Afghanistan War.
IEDs were also used extensively by cadres of the rebel Tamil Tiger (LTTE) organization against military targets in Sri Lanka.