8:45 a.m. (all times are EDT): A hijacked passenger jet, American Airlines Flight 11 out of Boston, Massachusetts, crashes into the north tower of the World Trade Center, tearing a gaping hole in the building and setting it afire.
9:03 a.m.: A second hijacked airliner, United Airlines Flight 175 from Boston, crashes into the south tower of the World Trade Center and explodes. Both buildings are burning.
9:17 a.m.: The Federal Aviation Administration shuts down all New York City area airports.
9:30 a.m.: President Bush, speaking in Sarasota, Florida, says the country has suffered an “apparent terrorist attack.”
9:40 a.m.: The FAA halts all flight operations at U.S. airports, the first time in U.S. history that air traffic nationwide has been halted.
9:43 a.m.: American Airlines Flight 77 crashes into the Pentagon, sending up a huge plume of smoke. Evacuation begins immediately.
9:45 a.m.: The White House evacuates.
9:57 a.m.: Bush departs from Florida.
10:05 a.m.: The south tower of the World Trade Center collapses, plummeting into the streets below. A massive cloud of dust and debris forms and slowly drifts away from the building.
10:08 a.m.: Secret Service agents armed with automatic rifles are deployed into Lafayette Park across from the White House.
10:10 a.m.: A portion of the Pentagon collapses.
10:10 a.m.: United Airlines Flight 93, also hijacked, crashes in Somerset County, Pennsylvania, southeast of Pittsburgh.
10:28 a.m.: The World Trade Center’s north tower collapses from the top down as if it were being peeled apart, releasing a tremendous cloud of debris and smoke.
11:02 a.m.: New York City Mayor Rudolph Giuliani urges New Yorkers to stay at home and orders an evacuation of the area south of Canal Street.
11:18 a.m.: American Airlines reports it has lost two aircraft. American Flight 11, a Boeing 767 flying from Boston to Los Angeles, had 81 passengers and 11 crew aboard. Flight 77, a Boeing 757 en route from Washington’s Dulles International Airport to Los Angeles, had 58 passengers and six crew members aboard. Flight 11 slammed into the north tower of the World Trade Center. Flight 77 hit the Pentagon.
11:26 a.m.: United Airlines reports that United Flight 93, en route from Newark, New Jersey, to San Francisco, California, has crashed in Pennsylvania. The airline also says that it is “deeply concerned” about United Flight 175.
11:59 a.m.: United Airlines confirms that Flight 175, from Boston to Los Angeles, has crashed with 56 passengers and nine crew members aboard. It hit the World Trade Center’s south tower.
1:04 p.m.: Bush, speaking from Barksdale Air Force Base in Louisiana, says that all appropriate security measures are being taken, including putting the U.S. military on high alert worldwide.
1:27 p.m.: A state of emergency is declared by the city of Washington.
2 p.m.: Senior FBI sources tell CNN they are working on the assumption that the four airplanes that crashed were hijacked as part of a terrorist attack.
2:30 p.m.: The FAA announces there will be no U.S. commercial air traffic until noon EDT Wednesday at the earliest.
3:55 p.m.: Giuliani now says the number of critically injured in New York City is up to 200 with 2,100 total injuries reported.
4:10 p.m.: Building 7 of the World Trade Center complex is reported on fire.
4:25 p.m.: The American Stock Exchange, the Nasdaq and the New York Stock Exchange say they will remain closed Wednesday.
4:30 p.m.: The president leaves Offutt Air Force Base in Nebraska aboard Air Force One to return to Washington.
5:20 p.m.: The 47-story Building 7 of the World Trade Center complex collapses. The evacuated building is damaged when the twin towers across the street collapse earlier in the day. Other nearby buildings in the area remain ablaze.
5:30 p.m.: CNN Senior White House Correspondent John King reports that U.S. officials say the plane that crashed in Pennsylvania could have been headed for one of three possible targets: Camp David, the White House or the U.S. Capitol building.
6 p.m.: Explosions are heard in Kabul, Afghanistan, hours after terrorist attacks targeted financial and military centers in the United States. The attacks occurred at 2:30 a.m. local time. Afghanistan is believed to be where bin Laden, who U.S. officials say is possibly behind Tuesday’s deadly attacks, is located. U.S. officials say later that the United States had no involvement in the incident whatsoever. The attack is credited to the Northern Alliance, a group fighting the Taliban in the country’s ongoing civil war.
6:10 p.m.:Giuliani urges New Yorkers to stay home Wednesday if they can.
6:40 p.m.: Rumsfeld, the U.S. defense secretary, holds a news conference in the Pentagon, noting the building is operational. “It will be in business tomorrow,” he says.
6:54 p.m.: Bush arrives back at the White House aboard Marine One and is scheduled to address the nation at 8:30 p.m. The president earlier landed at Andrews Air Force Base in Maryland with a three-fighter jet escort. CNN’s John King reports Laura Bush arrived earlier by motorcade from a “secure location.”
7:17 p.m.: U.S. Attorney General John Ashcroft says the FBI is setting up a Web site for tips on the attacks: www.ifccfbi.gov. He also says family and friends of possible victims can leave contact information at 800-331-0075.
7:02 p.m.: CNN’s Paula Zahn reports the Marriott Hotel near the World Trade Center is on the verge of collapse and says some New York bridges are now open to outbound traffic.
7:45 p.m.: The New York Police Department says that at least 78 officers are missing. The city also says that as many as half of the first 400 firefighters on the scene were killed.
8:30 p.m.: President Bush addresses the nation, saying “thousands of lives were suddenly ended by evil” and asks for prayers for the families and friends of Tuesday’s victims. “These acts shattered steel, but they cannot dent the steel of American resolve,” he says. The president says the U.S. government will make no distinction between the terrorists who committed the acts and those who harbor them. He adds that government offices in Washington are reopening for essential personnel Tuesday night and for all workers Wednesday.
9:22 p.m.: CNN’s McIntyre reports the fire at the Pentagon is still burning and is considered contained but not under control.
9:57 p.m.: Giuliani says New York City schools will be closed Wednesday and no more volunteers are needed for Tuesday evening’s rescue efforts. He says there is hope that there are still people alive in rubble. He also says that power is out on the westside of Manhattan and that health department tests show there are no airborne chemical agents about which to worry.
10:49 p.m.: CNN Congressional Correspondent Jonathan Karl reports that Attorney General Ashcroft told members of Congress that there were three to five hijackers on each plane armed only with knives.
10:56 p.m: CNN’s Zahn reports that New York City police believe there are people alive in buildings near the World Trade Center.
11:54 p.m.: CNN Washington Bureau Chief Frank Sesno reports that a government official told him there was an open microphone on one of the hijacked planes and that sounds of discussion and “duress” were heard. Sesno also reports a source says law enforcement has “credible” information and leads and is confident about the investigation.