Al-Qaida on Friday confirmed the killing of Osama bin Laden and warned of retaliation, saying Americans' "happiness will turn to sadness."

The confirmation came in an Internet statement posted on militant websites, signed by "the general leadership" of al-Qaida. The announcement opens the way for the group to name a successor to bin Laden. His deputy Ayman al-Zawahri is now the most prominent figure in the group and is a very likely contender to take his place.

The statement, dated May 3, was the first by the terror network since bin Laden was killed Monday by U.S. commandos in a raid on his hideout in Abbottabad, Pakistan. The statement's authenticity could not be independently confirmed, but it was posted on websites where the group traditionally puts out its messages.

"We stress that the blood of the holy warrior sheik, Osama bin Laden, God bless him, is precious to us and to all Muslims and will no go in vain," the statement said. "We will remain, God willing, a curse chasing the Americans and their agents, following them outside and inside their countries."

"Soon, God willing, their happiness will turn to sadness," it said, "their blood will be mingled with their tears."

In the statement, al-Qaida also called on the people of Pakistan _ "where Sheik Osama was killed" _ to rise up in revolt against its leaders. It also said that an audio message bin Laden recorded a week before his death would be issued soon.