When the end came

... for Bin Laden, he was found not in the remote tribal areas along the Pakistani-Afghan border where he has long been presumed to be sheltered, but in a massive compound about an hour’s drive north from the Pakistani capital of Islamabad. He was hiding in the medium-sized city of Abbottabad, home to a large Pakistani military base and a military academy of the Pakistani Army.

The house at the end of a narrow dirt road was roughly eight times larger than other homes in the area, but had no telephone or Internet connections. When American operatives converged on the house on Sunday, Bin Laden “resisted the assault force” and was killed in the middle of an intense gun battle, a senior administration official said, but details were still sketchy early Monday morning.

The official said that military and intelligence officials first learned last summer that a “high-value target” was being protected in the compound and began working on a plan for going in to get him. Beginning in March, Mr. Obama presided over five national security meetings at the White House to go over plans for the operation and on Friday morning, just before leaving Washington to tour tornado damage in Alabama, gave the final order for special forces and C.I.A. operatives to strike.

Mr. Obama called it a “targeted operation,” although officials said one helicopter was lost because of a mechanical failure and had to be destroyed to keep it from falling into hostile hands.

In addition to Bin Laden, three men were killed during the 40-minute raid, one believed to be his son and the other two his couriers, according to an American official who briefed reporters under White House ground rules forbidding further identification. A woman was killed when she was used as a shield by a male combatant, the official said, and two others wounded.

“No Americans were harmed,” Mr. Obama said. “They took care to avoid civilian casualties. After a firefight, they killed Osama bin Laden and took custody of his body.” Muslim tradition requires burial within 24 hours, but by doing it at sea, American authorities presumably were trying to avoid creating a shrine for his followers.

The fate of Ayman al-Zawahiri, the Al Qaeda second-in-command, was unclear Sunday night.

The terse announcement came just after 9:45 p.m. Sunday from Dan Pfeiffer, the White House communications director. “POTUS to address the nation tonight at 10:30 PM Eastern Time,” he wrote on Twitter, sharing the same message that had just been transmitted to the White House press corps.

According to Brian Williams, the “NBC Nightly News” anchor, some journalists received a three-word e-mail that simply read, “Get to work.”

The nation’s television anchors and newspaper editors did not know, at first, that President Obama would be announcing the death of Osama bin Laden, an extraordinary development in the nearly 10-year-long war against terrorism waged by the United States and its allies. But reporters in Washington suspected almost immediately that the announcement could be about bin Laden.

That speculation was not aired out on television immediately, but it did erupt on Twitter and other social networking sites. Wishful thinking about bin Laden’s death ricocheted across the Web — and then, at 10:25 p.m., while Mr. Obama was writing his speech, one particular tweet seemed to confirm it. Keith Urbahn, the chief of staff for the former defense secretary Donald Rumsfeld, wrote at that time, “So I’m told by a reputable person they have killed Osama Bin Laden. Hot damn.”