Dec. 22, 2004 -- -- Three weeks before the deadly attack on a U.S. base in Mosul, commanders at the base had a warning that insurgents were planning a "Beirut"-type attack on U.S. forces in northern Iraq, ABC News has learned. The warning prompted them to take additional unspecified security measures on the base.
On Tuesday, 22 people -- including 13 U.S. soldiers -- were killed in an attack on the crowded mess tent at Forward Operating Base Marez in Mosul. The Pentagon said today the deadly attack was apparently the work of a suicide bomber.
"At this point, it looks like it was an improvised explosive device worn by an attacker," said Gen. Richard Myers, chairman of the Joint Chiefs of Staff, adding, "I assure you that everything possible is being done to get to the bottom of what happened and to take the appropriate steps so that we can prevent future attacks of this nature."
Earlier, sources told ABC News that investigators at the base had determined the blast was a suicide attack after finding remnants of a torso and a suicide vest that was probably a backpack.
Weeks before Tuesday's attack, soldiers from the base intercepted a document that mentioned a proposal for a massive "Beirut"-type attack on U.S. forces. The reference was apparently to the October 1983 truck bombing of U.S. military barracks in the Lebanese capital in which 241 U.S. Marines were killed.
On Nov. 27, an ABC News reporter accompanying U.S. troops during a night raid in Mosul witnessed the rounding up of hundreds of Iraqis in the densely populated Old Town district.
During the roundup, one of the suspects tossed out several crushed sheets of handwritten notes from his pocket in an obvious effort to hide them from U.S. troops. A U.S. soldier at the site, however, noticed the fallen papers, picked them up and asked an interpreter present to translate the Arabic notes.
A U.S. official at the base later described the papers as a treasure trove of information. They contained "the minutes of some type of meeting of a terrorist cell that discussed money laundering, recruitment, weapons effectiveness and future operations," the official said. One of the possible future operations was described as a "Beirut"-type attack, and the notes referred to the importance of seeking and supplying information about Iraqis working for the U.S. military.