keywords: falluja zarqawi iraq abu attacks
text: U.S. Air Attacks in Falluja Kill 15 in 24 Hours  FALLUJA, Iraq (Reuters) - U.S. aircraft blasted the rebel  stronghold of Falluja for a third time in 24 hours in a  concerted effort to hit militants loyal to guerrilla chief Abu  Musab al-Zarqawi, Washington's number one enemy in Iraq.