U.S. military says January increase in bombs believed linked to Iran . Devices are known as EFPs ( explosively formed penetrators ) and can be used for a variety of purposes including detonating roadside bombs, destroying enemy tanks or other armored vehicles, and even penetrating underground bunkers where insurgents hide. EFPs increased by a factor of two or three over last 10 days . Bush administration , military say Iran arming , training Iraqi insurgents .
U.S. military says January increase in bombs believed linked to Iran . Devices are known as EFPs ( explosively formed penetrators ) Gen. Petraeus : EFPs increased by a factor of two or three over last 10 days . Bush administration , military say Iran arming , training Iraqi insurgents .