BAGHDAD, Iraq – America is preparing to launch a series of major operations against Al Qaeda in Iraq on the basis of key documents and contact details found in the operation that ended in the death of Al Qaeda’s leader in Iraq, Abu Musab al-Zarqawi.

As soon as Zarqawi’s death was confirmed yesterday morning, 17 simultaneous raids were launched against sites in the country, particularly in Baghdad.

President Bush hailed the American military yesterday for “delivering justice” to the terrorist who had taunted him for three years and eluded an intensive manhunt.

But Washington and London were united in cautioning that Zarqawi’s death in an air strike would not bring a swift end to the bloody insurgency in Iraq on its own.

A framed picture of the dead terrorist, shown bruised and bloated, was displayed at a triumphant Baghdad news conference, reinforcing the sense that the killing was a trophy operation.

It was the most significant success for American-led forces since the capture of Saddam Hussein in December 2003 and provided a piece of good news for Mr. Bush and Prime Minister Blair, who have been widely criticized for their inability to stem the relentless violence.

Zarqawi, who had a $25 million bounty on his head, was the most wanted man in Iraq for his masterminding of a string of suicide bombings, kidnappings, and murders, including the beheadings of the American contractor Nicholas Berg and the British engineer Ken Bigley.

The news of his death was welcomed by Mr. Bush, who was seen smiling while his leading advisers laughed in delight at a private meeting in the White House.

“This violent man will never murder again,” the president told reporters. “Special operations forces, acting on tips and intelligence from Iraqis, confirmed Zarqawi’s location and delivered justice to the most wanted terrorist in Iraq.” It was a “severe blow to Al Qaeda,” he said, but “we have tough days ahead of us in Iraq that will require the continuing patience of the American people.”

Mr. Blair welcomed the death of the “most vicious prosecutor” of terrorist violence. He added: “We should have no illusions. We know they will continue to kill; we know there are many, many obstacles to overcome. But they also know our determination to defeat them is total.”

A bloody reminder of the scale of the problems came yesterday when a string of bombs exploded across Baghdad, killing at least 40 people and wounding 67 others.

Zarqawi’s death was announced in the middle of the morning when Iraq’s prime minister, Nouri Al-Maliki, the American commander in Iraq, General George Casey, and the American ambassador, Zalmay Khalilzad, held a hastily arranged press conference. Mr. Maliki said the raid had followed a tip from local civilians.

The U.S. military said it had been zeroing in on Zarqawi’s position for two weeks. A vital clue to his whereabouts appears to have been a recent Internet message. In the end, Zarqawi’s spiritual adviser, Abu Abdul-Rahman al-Iraqi, was followed and he led troops to the terrorist’s hiding place. The adviser also was killed in the strike, as were five other people, including a women and a child.

An American soldier in Fallujah said: “It’s one step closer to finishing this job in the next 20 years. We’re obviously going to be here a long time.”

A Web site linked to Al Qaeda in Iraq celebrated the death as “martyrdom” and pledged to keep fighting “the holy war” in Iraq. Security was tightened across the country last night to try to thwart retaliatory attacks.

In a further piece of good news for Iraq, the country’s parliament approved new ministers of defense, the interior, and national security, ending weeks of intense negotiations between Sunni, Shiite, and Kurdish politicians.