FACTBOX - Breaking down the U.S. counterterrorism bureaucracy

REUTERS - President Barack Obama has summoned U.S. intelligence, counterterrorism and homeland security chiefs to a White House meeting on Tuesday to discuss how to prevent a repeat of the attempted bombing of a passenger jet on Dec. 25.

Turf battles between within the U.S. counterterrorism bureaucracy are nothing new. But lapses that allowed a Nigerian suspect to board a Detroit-bound plane with a bomb on Christmas Day, and the finger-pointing that followed, have raised questions about sweeping changes made to improve security and intelligence-sharing since the Sept 11, 2001, attacks.