Al-Qaeda and Islamic militants have vowed to avenge the killing of Osama bin Laden by US commandos, declaring him a "martyr" and calling on Muslims to rise up against the United States.
But US President Barack Obama swept aside the militants' defiant reaction, decorating the team that killed their inspirational leader and pledging the United States would crush Al-Qaeda.
"We have cut off their head and we will ultimately defeat them," Obama said Friday after meeting in private with the special forces personnel that raided bin Laden's hideout in Pakistan and shot dead the Al-Qaeda leader.
Confirming bin Laden's death for the first time, the terror network denounced his slaying urging Pakistani Muslims "to cleanse their country from the filth of the Americans who spread corruption in it."
The Afghanistan Taliban also joined the chorus of condemnation -- as small rallies were held after Friday prayers in several Islamic nations -- saying the loss of the architect of the September 11, 2001 attacks would only serve to strengthen its resolve in the fight against "foreign invaders."
"We call upon our Muslim people in Pakistan, on whose land Sheikh Osama was killed, to rise up and revolt to cleanse this shame," Al-Qaeda said in a statement released by the SITE monitoring group.
The Islamist group proclaimed its Saudi-born founder a "martyr," adding he had "terrified all the nations of disbelief." It vowed the jihadist network would survive, but did not name anyone to take over as its leader.
The White House said it was on alert for security threats as Al-Qaeda also vowed to release an audio tape made by bin Laden just a week before his death.
The Obama administration, embroiled in a decade-long war in Afghanistan, is keenly aware of the dangers facing US interests and nationals abroad.
US forces ousted the Taliban from power in 2001 following the 9/11 attacks in retaliation for harboring bin Laden on Afghan soil.
And the Taliban said bin Laden's death would "give a new impetus to the current jihad against the invaders in this critical phase of jihad," according to an email statement released by spokesman Tariq Ghazniwal.
Obama on Friday met the elite commando team that carried out the risky helicopter-borne raid on the fortified compound in the Pakistani town of Abbottabad where bin Laden was hiding.
He said he had told them "job well done" as he handed out Presidential Unit Citations, the highest unit award he has the power to grant, behind closed doors at an army base at Fort Campbell, Kentucky.
The meeting comes a day after Obama laid a wreath at Ground Zero, the site where the World Trade Center once stood, in a somber moment aimed at bringing closure to Americans still haunted by the September 11 attacks.
The White House has been eager to avoid triumphalism over the elimination of the world's most wanted man, blamed for the deaths of almost 3,000 people in the attacks, in a bid to avoid whipping up Muslim anger.
But on the traditional day of Muslim prayers, hundreds of Islamists rallied in Pakistan, Egypt, Turkey and Britain calling for revenge.
In Abbottabad, just 50 kilometers (30 miles) from the capital Islamabad, where bin Laden was finally tracked down after a years-long manhunt, police marshaled a rally of about 1,000 men.
Setting fire to tires and blocking a main road, the protesters yelled: "Down, down USA!" and "Terrorist, terrorist, USA terrorist."
Hundreds took to the streets in the insurgency-riven Pakistani city of Quetta calling for holy war against America, while Islamists also rallied in the Egyptian capital Cairo.
Intelligence seized during Monday's operation showed that despite his isolation bin Laden remained closely involved in Al-Qaeda operations up until his death.
The network had even been mulling strikes on US trains on the 10th anniversary of the 9/11 attacks, US officials said.
It is not yet clear how much bin Laden's death is likely to affect Al-Qaeda's operational capabilities and its ability to carry out attacks.
Questions have also been raised about how bin Laden managed to hide out for so long in Pakistan, in a town which is home to a top military academy and many retired generals.
Former Pakistan president Pervez Musharraf blamed the "incompetence" of his country's intelligence services, saying he was upset that bin Laden had been hiding in Pakistan when he was still in office.
In another sign of potential lapses by the Pakistani intelligence services, the Washington Post reported that the CIA had maintained a safe house in Abbottabad for several months to spy on bin Laden's compound.
The close-up spying operation allowed them to draw up the occupants' "pattern of life," the paper said.
The United States had intercepted a phone call to bin Laden's main courier, who told the caller that "I'm back with the people I was with before," the Post reported.
The call gave intelligence officials the courier's cellphone number. Using "a vast number of human and technical sources," the newspaper reported, they tracked the courier to the compound.
US officials learned that anyone leaving the compound would drive 90 minutes away before making calls, so as to avoid electronic surveillance, the Post reported.
The Obama administration has been forced to defend the raid's legality after acknowledging that bin Laden was unarmed when he was shot dead.
But new details have been released of the operation after conflicting accounts from the White House. The SEALs also found an AK-47 and a pistol in his room, a US official told AFP Thursday.
Meanwhile, The Los Angeles Times reported that at least one of the US special forces choppers used in the raid may have been a super-secret stealth helicopter, the likes of which have never been seen before.
Aerospace analysts who examined a picture of the surviving tail section of an aircraft that crash-landed at the site say the tail rotor of this modified Black Hawk was partially covered by a plate or hub, possibly part of a noise-muffling system, the paper said.
The analysis suggests that the military and CIA may have succeeded in their decades-old quest to develop a helicopter that can approach its target without being heard from miles away, the report said.