Years of tracking the world's most-wanted terrorist culminated Sunday afternoon, when a CIA-led Navy SEALs squadron of just a few dozen men stormed Usama bin Laden's compound and killed him.
President Obama announced the results of the top-secret operation late Sunday night, calling it the most significant blow to Al Qaeda to date. Within hours, the architect of the Sept. 11, 2001, attacks that killed more than 3,000 people was buried at sea.
Though the president offered only sparse information on the mission and the intelligence that led to it, details have since emerged about the heroic actions of the small, elite team dispatched to Pakistan by an order from the president last week.
According to officials, a 40-man Navy SEALs squadron raided bin Laden's compound in Abbottabad, Pakistan, at 3:30 p.m. ET on Sunday. As officials described it, the raid was swift -- the team was on the compound for less than 40 minutes and did not run into any local authorities during the firefight.
At the start of the operation, four U.S.-owned and operated helicopters launched from a base in Afghanistan and dropped about 24 men onto the grounds of the compound. One helicopter suffered a "hard landing" after experiencing a "flight control issue" and had to be destroyed on the site.
At first, bin Laden was asked to surrender. But a military official said he resisted. In the end, he was killed in the ensuing firefight with a bullet to the head.
No Americans were hurt or killed during the raid. Besides bin Laden, three other men were killed, one of whom is believed to be bin Laden's 24-year-old son. One woman used as a human shield was also killed, and two other women were injured.
The operation itself stemmed from a tip that came to Obama's desk last August. Specifically, U.S. officials were tracking an Al Qaeda courier in Pakistan, based on information obtained from multiple detainees, and determined the location of the compound in Pakistan where the courier and his brother operated. It was built on a large plot of land, and was heavily secured, with 12-to-18-foot walls topped with barbed wire, officials said. Intelligence analysts determined the compound "was custom-built to hide someone of significance," a senior administration official said.
After months of analyzing the information, U.S. officials began holding high-level meetings about how to proceed earlier this year.
On April 29, Obama gave the order to conduct the operation. The actual mission was supposed to happen Saturday night, but it was delayed due to weather.
The highly trained special forces unit had been practicing the raid a week in advance.
In announcing the successful completion, Obama said Sunday night that bin Laden's death "is a testament to the greatness of our country."
"For over two decades, bin Laden has been Al Qaeda's leader and symbol," Obama said. "The death of bin Laden marks the most significant achievement to date in our nation's effort to defeat Al Qaeda."
In a message to employees, CIA Director Leon Panetta said Monday that "we have rid the world of the most infamous terrorist of our time."
"Nothing will ever compensate for the pain and suffering inflicted by this mass murderer and his henchmen. But just as evil never rests, neither does good. May the fact that Usama Bin Ladin no longer inhabits the earth be a source of comfort for the thousands of families, here in America and around the globe, who mourn the victims of Al Qaeda's barbarity," he wrote.
He added that while bin Laden is dead, "Al Qaeda is not."
In the wake of bin Laden's death, authorities around the world are being urged to take security precautions. One source said officials are concerned bin Laden's death could incite violence or terrorist acts against U.S. personnel overseas.
The State Department issued a travel alert for U.S. citizens abroad overnight, citing "the enhanced potential for anti-American violence given recent counterterrorism activity in Pakistan."
Obama said Americans must continue to be "vigilant." But he said the death of the architect of the deadliest terror attack on U.S. soil should be welcomed around the world.
"Bin Laden was not a Muslim leader. He was a mass murderer of Muslims," Obama said. "So his demise should be welcomed by all who believe in peace and human dignity."
Fox News' Jennifer Griffin, Justin Fishel and Catherine Herridge contributed to this report.