Osama Bin Laden is dead, President Obama announced Sunday night, in a televised address to the nation. His death was the result of a U.S. operation launched today in Abbottabad, Pakistan, against a compound where bin Laden was believed to be hiding, according to U.S. intelligence. After a firefight, a small team of American forces killed bin Laden and took possession of his body, the president said.

“Tonight I can report to the American people and the world that the United States has conducted an operation that killed Osama bin Laden,” Obama said during brief remarks at the White House.

“Justice has been done,” he said, in comments that marked a formal end of the manhunt for the most visible and emotionally-charged symbol of the terrorist attacks of Sept. 11, 2001.

The president said U.S. intelligence operatives received a tip in August on bin Laden’s whereabouts, which ultimately led to Sunday’s attack. Obama said he determined last week that the U.S. had enough reliable information to take action; by Sunday morning, he had authorized “a small team of Americans” to conduct an operation targeting bin Laden.

“After a fire fight, they killed Osama bin Laden and took custody of his body,” the president said. “No Americans were harmed. They took care to avoid civilian casualties.”

Obama said the 9/11 attacks that bin Laden and his lieutenants orchestrated nearly 10 years ago remain “the worst attack on the American people in our history” and said the images of the crumbling Twin Towers “are seared into our national memory.”

The president emphasized that Americans “did not choose this fight” against al Qaeda, but rather, “it came to our shores.” He praised U.S. military and intelligence professionals for working “tirelessly to achieve this outcome.” To the families of 9/11 victims, he noted that the U.S. has “never forgotten your loss.”

“Tonight, let us think back to the sense of unity that prevailed on 9/11,” Obama said. “I know that it has, at times, frayed. Yet today’s achievement is a testament to the greatness of our country and the determination of the American people.”

Both Bill Clinton and George W. Bush had targeted bin Laden during their presidencies, and both had failed to either capture him or kill him. The failure to snare bin Laden weighed most heavily, perhaps, on the Bush Administration, which occupied the White House during the 9/11 attacks, and the al Qaeda leader’s killing falls exactly eight years to the day when Bush famously declared “Mission Accomplished” in Iraq.

Bush said in a statement that Obama called him Sunday night to inform him of “the momentous achievement” of bin Laden’s death.

“I congratulated him and the men and women of our military and intelligence communities who devoted their lives to this mission. They have our everlasting gratitude,” Bush said. “The fight against terror goes on, but tonight America has sent an unmistakable message: No matter how long it takes, justice will be done.”

Clinton, who was president when the first World Trade Center bombing occurred in 1993, issued a statement calling bin Laden’s death “a profoundly important moment not just for the families of those who lost their lives on 9/11 and in al-Qaida’s other attacks but for people all over the world who want to build a common future of peace, freedom, and cooperation for our children.”

In a conference call with reporters just after President Obama spoke, senior administration officials provided a detailed sketch of how the intelligence on bin Laden’s whereabouts was gathered.

Intelligence officials had been conducting lengthy reconnaissance work prior to receiving their key tip in August. According to senior administration officials, suspected terrorists in custody since 9/11 -- including the attack’s mastermind, Khalid Sheikh Mohammed -- identified a courier who had a close relationship with bin Laden.

“This man was one of the few al Qaeda couriers trusted by bin Laden,” one senior administration official said. “They indicated he might be living with and protecting bin Laden. But for years we were unable to identify his true name or his location. Four years ago we uncovered his identity… About two years ago, after months of persistent effort, we identified areas of Pakistan where the courier and his brother operated. Still, we were unable to pinpoint exactly where they lived due to extensive operational security on their part. The fact that they were being so careful reinforced our belief that we were on the right track.”

When the intelligence community finally pinpointed the courier’s location, they were “shocked by what we saw,” said this official.

The neighborhood in Abbottabad was “relatively affluent with lots of retired military,” this official continued, and was insulated from urban areas or places susceptible to natural disaster and terrorist attacks. The home was “roughly eight times larger than the other homes in the area,” and it was surrounded by 12-to-18-foot-high walls, topped with barbed wire. It had two security gates and a value of roughly $1 million, although it lacked telephone and Internet connections.

An even more telling clue for intelligence operatives: The occupants of the house were burning their trash rather than putting it out for collection.

One senior administration official suggested bin Laden had been staying at the compound for at least six months without moving. Bin Laden was known to have regularly shifted locations to evade capture, so it’s unusual that he chose to stay in on spot for such an extended period.

More recently, the Obama administration had reduced the number of drone strikes in the area -- while ramping up surveillance -- in an effort to give the al Qaeda leader a heightened sense of safety in his home.

Prior to the operation, Obama convened nine meetings with his national security team to review intelligence. According to a White House aide, “Principals met formally an additional five times themselves and their deputies met seven times.”

The president made the decision to undertake the operation at 8:20 a.m. on April 29th in the White House’s Diplomatic Room before he left to survey tornado damage in Alabama. Tom Donilon, his National Security Advisor, prepared the formal orders and convened the principals at 3 p.m. that same day to complete the planning.

The next day, without giving off a hint of the weighty operation being planned, Obama prepared for and delivered his address at the annual White House Correspondent's Association dinner. The next morning he played nine holes of golf.

Final preparations were made on Sunday. At 2 p.m., the president met with top advisers for an hour and half, at which point he returned to the Situation Room for an additional briefing. Twenty minutes after that, he learned that bin Laden had been “tentatively identified.” By 7 p.m. he was told it was highly probable that bin Laden was at the compound. By 8:30 p.m., he received an additional briefing. He signed off on the attack after that.

No other intelligence operatives in other countries were told of the attack before it occurred -- including Pakistani operatives -- according to administration officials. Vice President Joseph Biden informed congressional leadership of the attack shortly before it took place, aides on the Hill told the Huffington Post.

Details about the fight itself are still difficult to come by. According to local reports in Pakistan, a helicopter involved in the attack had a mechanical problem and crashed.

U.S. forces intentionally destroyed the remainder of the wreckage to reduce signs of their presence in the area , according to NBC and other media reports. Two helicopters remained to provide cover for Joint Special Operations Command forces; in addition, there was a predator drone.

The fight lasted only 40 minutes and was described by a senior administration official as a “surgical raid” conducted by a Navy Seals unit. Bin Laden's adult son was killed, as were two of his couriers and a woman being used as a human shield. Bin Laden himself “did resist the assault force,” a senior administration official said. Reports on Sunday night said the terrorist leader was ultimately shot in the head.

Officials warned that in the aftermath of the attack, Americans should be on alert for a reprisal from al Qaeda. However, one official added, there were “no specific threats" as of Sunday night. ABC News reported that authorities plan to bury bin Laden’s body at sea in order to leave no definitive location for his final resting place. It will be done, an official added, “in accordance with Islamic practice and tradition." Hours later, CNN reported that the burial had taken place.

"Americans understand the costs of war," Obama said toward the end of his remarks. "Yet as a country, we will never tolerate our security being threatened, nor stand idly by when our people have been killed. We will be relentless in defense of our citizens and our friends and allies."

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Watch: Obama: Osama Bin Laden Killed by U.S. Forces

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