(CNN) -- In the dark of night, U.S. helicopters approached a high-walled compound in Pakistan on a mission to capture or kill one of the world's most notorious terrorist leaders. Less than 40 minutes later -- early Monday morning in Pakistan -- Osama bin Laden was dead, along with four others inside the complex, and the U.S. forces departed with the slain al Qaeda leader's body to fulfill a vow that originated shortly after the September 11, 2001, terrorist attacks on the United States. And as he announced the raid at the White House Sunday night, U.S. President Barack Obama called bin Laden's death "the most significant achievement to date in our nation's effort to defeat al Qaeda."
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NEW: A senior official says "Geronimo" was code for the capturing or killing of bin Laden
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NEW: The woman killed during the operation may not have been bin Laden's wife
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Authorities call the raid a surgical strike
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Sources say bin Laden resisted the assault and was shot in a firefight
This official and others briefed reporters on further details about the assault on the compound, which they believe was built five years ago for the specific purpose of hiding bin Laden -- known by the code name "@placeholder," a U.S. official said.