Al Qaeda leader Osama bin Laden was killed in an overnight firefight with US forces in Pakistan, President Barack Obama has confirmed, ending a nearly 10-year worldwide hunt for the mastermind of the September 11th attacks.
"This is a good day for America," the president said this afternoon during an address to a White House audience gathered for an awards ceremony.
"Today we are reminded that as a nation there is nothing we can't do," Mr Obama said.
An team of American forces killed bin Laden during the overnight raid. It is understood Bin Laden was shot twice in the head during a firefight and then quickly buried at sea.
White House officials are thought to be considering the merits and appropriateness of releasing a photo.
"The United States has conducted an operation that killed Osama bin Laden, the leader of al Qaeda and a terrorist who is responsible for the murder of thousands of men, women and children," Mr Obama said.
No Americans were killed in the operation and they took care to avoid civilian casualties, he said.
Intelligence that originated last August provided the clues that eventually led to bin Laden's trail, the president said. A US official said Mr Obama gave the final order to pursue the operation last Friday morning.
A senior administration official said it was believed that three adults besides bin Laden were killed, including a woman and an adult son of bin Laden.
Bin Laden's death, confirmed by officials in Pakistan, is a symbolic blow to al Qaeda, which has been beaten back but is still a threat in many countries.
It prompted jubilant flag-waving celebrations in Washington and New York and is the biggest national security victory for Mr Obama since he took office in early 2009. Mr Obama will hope it will give his campaign a political boost as he seeks re-election in 2012.
Mr Obama may now find it easier to end the nearly decade-old war in Afghanistan, begun after the September 11th, 2001, attacks on New York and Washington that killed nearly 3,000.
But the operation could complicate relations with Pakistan already frayed over US drone strikes in the west of the country and the jailing of a CIA contractor accused of killing two Pakistani men.
Bin Laden's death triggered a travel alert for Americans worldwide, the US State Department said, warning of the potential for anti-American violence.
Thousands of people gathered outside the White House, waving American flags, cheering and chanting "USA, USA, USA." Car drivers blew their horns in celebration and people streamed to Lafayette Park across from the street, as police vehicles with their lights flashing stood vigil.
Similar celebrations erupted in New York's Ground Zero, site of the World Trade Center twin towers felled by hijacked airplanes on September 11th.
Newly appointed CIA director Leon Panetta says al Qaeda will "almost certainly" attempt to avenge bin Laden's death.
Former President George W. Bush, who vowed to bring bin Laden to justice "dead or alive" but never did, called the operation a "momentous achievement" after Mr Obama called him with the news.
Statements of appreciation poured in from both sides of Washington's often divided political divide. Republican Senator John McCain declared, "I am overjoyed that we finally got the world's top terrorist."
Said former President Bill Clinton: "I congratulate the president, the national security team and the members of our armed forces on bringing Osama bin Laden to justice after more than a decade of murderous al Qaeda attacks."
Having the body may help convince any doubters that bin Laden is really dead.
While in hiding, bin Laden had taunted the West and advocated his militant Islamist views in videotapes spirited from his hideaway.
Besides September 11, Washington has also linked bin Laden to a string of attacks - including the 1998 bombings of American embassies in Kenya and Tanzania and the 2000 bombing of the warship USS Cole in Yemen.
Additional reporting: Agencies