U.S. President Barack Obama has confirmed in a speech to the nation that Osama bin Laden, leader of the Al-Qaeda terror group who has been sought by the U.S. for nearly a decade due to his group’s involvement in the September 11 terror attacks on the World Trade Center, is dead.

"Justice has been done", he said, addressing his words in particular to the families of those killed in 9/11, in the war against the Taliban and also thanking those servicemen and women who took part in the search for the terrorist leader.

In his speech, Obama confirmed the reports that bin Laden had been killed in Pakistan during a firefight in a compound outside Islamabad. He noted that the information about bin Laden's whereabouts had been given to him last August and that he authorized the operation last week.

"He was a mass murderer of Muslims," said Obama, warning that vigilance must continue in case of reprisals. Cheering crowds with hastily made signs gathered outside the White House shortly after  the news broke.

Major news agencies reported prior to Obama's speech that bin Laden was killed in a mansion between Islamabad and Peshawar in Pakistan. The CNN network noted that he was killed by American forces. It was also reported that a DNA test had proven that it was indeed bin Laden who had been killed.

A Pakistani intelligence official confirmed that bin Laden had indeed been killed in Pakistan, AP said.

In his speech, Obama said that bin Laden's killing is proof that the U.S. can do what it sets out to do, because it is a land "under God, with liberty and justice for all."

After positive identification of his remains, Bin Laden was buried at an undisclosed location at sea.