Today's attack came after 12 days of bombardment on Afghanistan. In light of the raid, the increasing pace of airstrikes in recent days suggests that the Pentagon wanted to prepare the way for this ground attack.
Earlier this week, U.S. forces began deploying AC-130 gunships, which pump out cannon and artillery fire at a withering 2,500 rounds per minute and are used to provide cover to special assault teams entering a region.
It was unclear how the U.S. force reached the scene. U.S. special operations teams have recently been aboard the carrier Kitty Hawk, hundreds of miles away from Afghanistan in the Arabian Sea.
Daniel Goure, a former defense official now at the Lexington Institute, said U.S. forces have just received permission to use a base just south of Kandahar on the Pakistani side of the border.
Goure said the attack likely had several goals: to find key figures, to wreak destruction "and to make clear that this will be a war unlike anything the Afghans have seen."
He said the U.S. forces were taking full advantage of technology that allows them to fight at night against an opponent that lacks such capability.
The U.S. military's special operations forces includes the Green Berets, Navy SEALs, a clandestine unit called Delta Force and Air Force Air Commandos.
In all, the U.S. has 46,000 special operations troops, with each unit trained to carry out different type of missions by land, sea and air. They include experts at counter-terrorism, reconnaissance and guerrilla warfare. Working in teams of 12, they generally drop from helicopters behind enemy lines.
Military analysts believe that any effort to locate and capture Bin Laden would probably fall to the prestigious Delta Force, which specializes in daring hostage rescues and kidnappings.
In a sign that the entry of perhaps significant numbers of U.S. ground troops into Afghanistan could be imminent, the Pentagon released the transcript of messages broadcast to Afghans from aircraft over the past few days.
Afghans were advised that once U.S. ground forces arrived, the safest place to be in would be their homes.
"Attention. People of Afghanistan, United States forces will be moving through your area. . . . Please, for your own safety, stay off bridges and roadways, and do not interfere with our troops or military operations," the broadcasts said.
"If you see United States forces, you need to find shelter and not leave it until we have left the area. . . . Your home will be the safest place."
