America's number one enemy 'was killer'

America's most wanted enemy in Iraq emerged from the shadows last night to appear on video apparently cutting off the head of the American businessman Nick Berg.

America's most wanted enemy in Iraq emerged from the shadows last night to appear on video apparently cutting off the head of the American businessman Nick Berg.

Abu Musab al-Zarqawi, an al-Qa'ida operative who is a close ally of Osama bin Laden, was the man wielding the knife that slit Mr Berg's throat, according to the Islamist website that broadcast the video entitled "Abu Musab al-Zarqawi shown slaughtering an American".

The one-legged Jordanian has been high on America's hit list since the US Secretary of State, Colin Powell, accused him ­ the month before the Iraq invasion ­ of leading a "deadly terrorist network", plotting attacks in Europe.

Most recently, Zarqawi has been suspected of masterminding attacks in Iraq, including the massacre of Shia pilgrims in Karbala and Baghdad on 2 March in an apparent attempt to foment civil war. He has claimed responsibility for attacks on US and other Allied forces since the fall of Saddam Hussein. The US has attributed to Zarqawi a letter on a CD-Rom in which he warned of attacks on the majority Shia population with the aim of provoking a Sunni-Shia civil war to wreck the US plans to pull out of Iraq on 30 June. The letter was apparently from Zarqawi to his superiors, possibly Osama bin Laden.

Last month, in an audio tape on an Islamist website, he issued a fresh warning to the "snakes of evil". The tape said: "Sharpen your swords and burn the ground under the invaders' feet. Fight the Americans, fight the rejectionists [Shia] and the agents and hypocrites."

The US has offered $10m for information leading to the capture or killing of Zarqawi, whose real name is Ahmad Fadheel al-Khalayleh.

He was sentenced to death in absentia last year for plotting attacks on Westerners in Jordan. On 6 April, he received a death sentence in absentia, along with seven other al-Qa'ida militants, for killing Laurence Foley, an American aid worker, in Amman in 2002.

His nephew, 19-year-old Omar al-Khalayleh, was one of three men jailed for three years in Jordan on Monday for plotting attacks on US and Jewish tourists. They were also accused of plotting attacks on shops selling alcohol in Amman, the Jordanian capital, and on state investigators seeking to root out and prosecute Islamic militants.

Zarqawi's name surfaced most prominently during the US Secretary of State's presentation to the United Nations in February last year laying out the justification for war with Iraq. General Powell alleged that Zarqawi had gone to north-east Iraq from Afghanistan following the Taliban's fall and set up a cell with an Islamist group, Ansar al-Islam, specialising in the production of deadly poisons.

He claimed that a Baghdad agent had sanctioned Zarqawi's presence and offered him safe haven. Zarqawi was said to have sought medical treatment in Baghdad in May 2002, where his leg was amputated.

Ansar's leader, Mullah Krekar, later denied any link with either Saddam or al-Qa'ida, and General Powell's allegations were largely dismissed, along with the rest of his speech, which presented now-discredited evidence of Iraqi possession of weapons of mass destruction.