For years, Osama Bin Laden\'s charisma kept Al Qaida\'s ranks filled with zealous recruits. But it was the strategic thinking and the organizational skills of his Egyptian right hand man that kept the terror network together after the United States invaded Afghanistan in 2001 and pushed Al Qaida out. With Bin Laden killed, Ayman Al Zawahri becomes the top candidate for the world\'s top terror job. Analysts predict that under Al Zawahri, Al Qaida would likely be further radicalised, unleashing a new wave of attacks to avenge Bin Laden\'s killing by US troops in Pakistan on Monday to send a message that it\'s business as usual. Al Zawahri is known for his extremist views and his readiness to use deadly violence. The alliance established Al Zawahri as bin Laden\'s deputy and soon after came the bombings of the US embassies in Africa, followed by the 2000 suicide bombing of the USS Cole off the coast of Yemen, an attack Al Zawahri is believed to have helped organise. Bin Laden killed Sunday Islamabad/Washington: Al Qaida leader Osama Bin Laden was killed Sunday in a firefight with US forces in Pakistan and his body was recovered, President Barack Obama said on Sunday. \"Justice has been done,\" Obama said in a dramatic, late-night White House speech announcing the death of the elusive mastermind of the 9/11, 2001, attacks on New York and Washington that killed nearly 3,000 people. It is was major accomplishment for Obama and his national security team and could give him a political boost as he seeks re-election in 2012. And it was at least a huge symbolic blow to Al Qaida, the militant organization that has staged bloody attacks in many western and Arab countries cities and has been the subject of a worldwide campaign against it. Obama said US forces led a targeted operation that killed Bin Laden in Abbotabad north of Islamabad. No Americans were killed in the operation and they took care to avoid civilian casualties, he said. In Washington, thousands of people gathered quickly outside the White House, waving American flags, cheering and chanting \"USA, USA, USA.\" Car drivers blew their horns in celebration and people streamed to Lafayette Park across from the presidential mansion. Police vehicles with their lights flashing stood vigil. \"I\'m down here to witness the history. My boyfriend is commissioning as a Marine next week. So I\'m really proud of the troops,\" Laura Vogler, a junior at American University in Washington, said outside the White House. Many Americans had given up hope of ever finding bin Laden after he vanished in the mountains of eastern Afghanistan in late 2001 as U.S. and allied forces invaded the country in response to the Sept. 11 attacks. Intelligence that originated last August provided the clues that eventually led to bin Laden\'s trail, the president said. A U.S. official said Obama gave the final order to pursue the operation last Friday morning. \"The United States has conducted an operation that killed Osama bin Laden, the leader of Al Qaida and a terrorist who is responsible for the murder of thousands of men, women and children,\" Obama said. A crowd gathered in Lafayette Park outside the White House erupted in jubilation at the news. Hundreds of people waved flags, hugged and cheered. According to intelligence officials, bin Laden was killed in a helicopter raid on a mansion in an area north of the Pakistani capital. Four helicopters launched the attack in the Bilal area of Abbottabad, about 100 kilometers north of Islamabad, said a Pakistani intelligence official. One of the helicopters crashed after it apparently was hit by fire from the ground, the official said. He gave no word on casualties. He said the helicopters took off from a Pakistani air base in the north of the country. Women and children were taken into custody during the raid, he said. He spoke on condition of anonymity because of the sensitivity of the information. A US official, also speaking on condition of anonymity, confirmed that the raid was on a mansion close to Islamabad. The operation also left three other men and a woman dead, including a son of the Al Qaida chief, officials said. \"In addition to Osama bin Laden, three adult males were killed in the raid,\" a US official, who spoke on condition of anonymity, told reporters. Two of the men worked as couriers for Bin Laden and the third was believed to be an adult son of Bin Laden, the official said. \"One woman was killed when she was used as a shield by a male combatant. Two other women were injured\" in the raid that lasted less than 40 minutes, the official added. Former President George W. Bush, who famously vowed to bring bin Laden to justice \"dead or alive\" but never did, called the operation a \"momentous achievement\" after Obama called him with the news. Statements of appreciation poured in from both sides of Washington\'s often divided political divide. Republican Senator John McCain declared, \"I am overjoyed that we finally got the world\'s top terrorist.\" Said former President Bill Clinton: \"I congratulate the president, the national security team and the members of our armed forces on bringing Osama bin Laden to justice after more than a decade of murderous al Qaeda attacks.\" Having the body may help convince any doubters that bin Laden is really dead. Bin Laden had been hunted since he eluded US soldiers and Afghan militia forces in a large-scale assault on the Tora Bora mountains of Afghanistan close to the Pakistan frontier in 2001. The trail quickly went cold after he disappeared and many intelligence officials believed he had been hiding in Pakistan. While in hiding, Bin Laden had taunted the West and advocated his militant Islamist views in videotapes spirited from his hideaway. Besides 9/11, Washington has also linked bin Laden to a string of attacks -- including the 1998 bombings of American embassies in Kenya and Tanzania and the 2000 bombing of the warship USS Cole in Yemen.