Feb. 14: An assault by dozens of insurgents on a police station kills 25 people in Fallujah, most of them Iraqi policemen.

March 24: After a six-month tour, U.S. 82nd Airborne hands authority for Fallujah to U.S. Marines.

March 31: Gunmen in Fallujah attack cars carrying four American contractors, killing them and setting the vehicles afire. Angry crowds drag the bodies through the streets, dismember and mutilate the corpses.

April 5: Marines seal off Fallujah; siege begins.

April: During the month, U.S. warplanes repeatedly strike targets in the city, killing dozens of people. Repeated talks fail to halt the battles. Cease-fires fail.

May 1: Under mounting international criticism, all 700 Marines pull out, turning the city over to the "Fallujah Brigades," a new force made up largely of former Iraqi soldiers. The brigade fails to maintain control; the city falls into the hands of militants and radicals.

May 8: American Nicholas Berg's beheaded body is found in Baghdad. His decapitation is claimed by followers of Jordanian Abu Musab al-Zarqawi - the first of at least nine foreigners slain by al-Zarqawi loyalists.

June 19: U.S. warplanes target safehouses in Fallujah used by followers of al-Zarqawi, in first significant attack since end of the siege. July 5: American forces drop bombs on a purported militant safehouse in Fallujah, killing at least 10 people. Interim Iraqi Prime Minister Ayad Allawi says his government provided intelligence for the strike.

August and September: U.S. jets repeatedly strike Fallujah.

Oct. 13: Allawi threatens military action against Fallujah if residents don't hand over al-Zarqawi. Two days later, Fallujah clerics insist that al-Zarqawi is not in the city.

Early November: U.S. military planes launch attacks on Fallujah. Allawi warns "window is closing" for peaceful settlement to avert a U.S. assault.

Monday: U.S. and Iraqi forces begin latest assault on Fallujah.