WASHINGTON — After nearly a decade of anger and fear, America rejoiced Monday at the demise of Osama bin Laden, the terror mastermind behind the horrific 9/11 attacks. Navy SEALs who killed the world’s most-wanted terrorist seized a trove of Al Qaeda documents to pore over, and President Obama laid plans to visit New York’s ground zero.

Bin Laden, killed in an intense firefight in a daring raid at his fortified hideout in Pakistan, was hunted down based on information first gleaned years ago from detainees at secret CIA prison sites in Eastern Europe, officials disclosed.

His body was quickly taken away for burial at sea, but not before a DNA match was done to prove his identity. A U.S. official said there also were photos showing bin Laden with the fatal wound above his left eye, a gunshot that tore away part of his skull. The photos were not immediately released.

"The world is safer. It is a better place because of the death of Osama bin Laden," Obama declared, hours after U.S. forces killed the Qaeda leader in the middle-of-the-night raid on his compound in Abbottabad. Obama was expected to visit New York, the site of Al Qaeda’s attack on the World Trade Center, and meet with the families of those killed, an administration official said.

The CIA already was poring over confiscated hard drives, DVDs, and other documents looking for inside information on Al Qaeda, including clues that might lead to his presumed successor, Ayman al-Zawahri.

Obama reaped accolades from world leaders he’d kept in the dark about the operation as well as plaudits from political opponents at home. Republican and Democratic congressional leaders alike gave him a standing ovation at an evening meeting that was planned before the assault but became a celebration of its success.

"Last night’s news unified our country" much as the terrorist attacks of 2001 did, Republican House Speaker John Boehner said earlier in the day. Obama later appealed for that unity to take root as the U.S. presses the fight against a terrorist network that is still lethal — and vowing vengeance.

The SEALs dropped down ropes from helicopters at the compound, killed bin Laden aides, and made their way to the main building, where U.S. officials say the terror leader was slain in a gunfight.

Within 40 minutes the Americans were gone, taking bin Laden’s body to the USS Carl Vinson, where he was slipped into the sea.

"For my family and me, it’s good, it’s desirable, it’s right," said Mike Low of Batesville, Ark., whose daughter Sara was a flight attendant aboard the hijacked plane that was flown into the World Trade Center North Tower. "It certainly brings an ending to a major quest for all of us."

Halfway around the world, a prominent Qaeda commentator vowed revenge for bin Laden’s death.

"Woe to his enemies. By God, we will avenge the killing of the Sheik of Islam," he wrote under his online name Assad al-Jihad2. "Those who wish that jihad has ended or weakened, I tell them: Let us wait a little bit."

U.S. officials conceded the risk of renewed attack. The terrorists "almost certainly will attempt to avenge" bin Laden’s death, CIA Director Leon Panetta wrote in a memo that congratulated the agency for its role in the operation. "Bin Laden is dead. Al Qaeda is not."

Within a few hours, the Department of Homeland Security warned that bin Laden’s death was likely to provide motivation for attacks from "homegrown violent extremists" seeking revenge."

FBI spokesman Paul Bresson said, "While there are no specific, bin Laden-related threats at this time, every logical and prudent step is being taken to mitigate any developing threats." There were questions, as well, about Pakistan’s role in bin Laden’s years in hiding. Both Obama and Secretary of State Hillary Rodham Clinton said cooperation from the Pakistani government had helped lead U.S. forces to the compound where he died.

But John Brennan, White House counterterrorism adviser, told reporters it was inconceivable that the terrorist fugitive didn’t have some support in Pakistan, where his hideout had been custom built six years ago in a city with a heavy military presence. "I am not going to speculate about what type of support he might have had on an official basis," he added.

By their condemnations, bin Laden’s supporters confirmed his death in what U.S. officials said was an operation years in the making. Even so, officials were weighing the release of at least one photo taken of bin Laden’s body as part of what Brennan called an effort to make sure "nobody has any basis to try to deny" the death.

U.S. officials said the information that ultimately led to bin Laden’s capture originally came from detainees held in secret CIA prison sites in Eastern Europe. There, agency interrogators were told of an alias used by a courier whom bin Laden particularly trusted.

It took four long years to learn the man’s real name, then years more before investigators got a big break in the case, these officials said. Sometime in mid-2010, the man was overheard using a phone by intelligence officials, who then were able to locate his residence — the specially constructed $1 million compound with walls as high as 18 feet topped with barbed wire.

U.S. counterterrorism officials considered bombing the place, an option that was discarded by the White House as too risky, particularly if it turned out bin Laden was not there.

Brennan said the president and his aides "were able to monitor in a real-time basis the progress of the operation" from beginning to end.

According to officials who declined to be identified by name, bin Laden was shot in the head during a firefight, and his body was identified to near 100 percent certainty through DNA testing. Photo analysis by the CIA, confirmation by a woman believed to be one of bin Laden’s wives, who was also at the compound, and matching physical features added confirmation, they said.