U.S. intelligence officials believe that Ayman al-Zarqawi, a Jordanian militant with links to Osama bin Laden's al-Qaida network, has orchestrated the vast majority of terror attacks against U.S. forces and members of the U.S.-supported police and government since the invasion in March 2003.
Al-Zarqawi, who fought against both the Soviets and U.S. troops in Afghanistan, made his way through Iran and Iraq to a small settlement named Khurmal in northern Iraq where he established a radical Islamic group, Ansar al Islam.
Below is a list of the most deadly strikes blamed on al-Zarqawi, on whose head the United States has placed a $25 million ransom.
--Aug. 7, 2003
A truck bomb explodes outside the Jordanian embassy in Baghdad, killing 17 people and wounding more than 60. It is the first terrorist bombing in Baghdad since the United States captured the city.
--Aug. 19, 2003
A truck bomb wrecks U.N. headquarters in Baghdad, killing 24 people, including U.N. envoy Sergio Vieira de Mello, and wounding at least 100. The blast is found to have been caused by the same combination of explosives and ammunition as the Jordanian embassy.
--Aug. 29, 2003
Two car bombs detonated by suicide bombers explode outside the Imam Ali Shrine in Najaf, one of the Shia faith’s most sacred shrines, killing 125 people, including the leader of the nation's Shia community, Grand Ayatollah Mohammed Baqr al-Hakim. Al-Zarqawi is suspected in what is at the time the worst attack ever by al-Qaida or associated groups that is aimed at Muslims.
--Sept. 2, 2003
A car explodes near a police academy in central Baghdad, killing one. The bomb is, again, a combination of explosive and ammunition, like the bombs used at the Jordanian embassy and U.N. headquarters.
--Sept. 9, 2003
In a daring but failed attempt to inflict large-scale casualties on U.S. troops, a suicide bomber detonates a car bomb outside a military housing in Arbil in northern Iraq. The design and security measures around the facility thwart the attack, but still one American soldier is killed.
Oct. 9, 2003
In the first attack on an Iraqi police station, a suicide bomber detonates a car bomb outside a station in Sadr City, the predominantly Shia neighborhood in northern Baghdad. At least 10 people are killed in the attack, believed to be aimed at both Iraqi “collaborators” with the U.S. forces and Shites.
--Oct. 12, 2003
An ambulance or a vehicle disguised as an ambulance explodes outside the Shaheen Hotel in Baghdad, a hotel used by foreigners, including Americans. The bomb kills 6, and once again,
--Oct. 14, 2003
A car driving by the Turkish embassy in Baghdad explodes, killing the driver, but wounding only two security guards. It is the first attack against a Turkish facility by Islamic fundamentalists. A month later, it will be followed by four attacks in the moderate Islamic country.
--Oct. 27, 2003
In a daylong series of attacks against Iraqis working with occupation troops, five suicide bombers blow up vehicles at four Baghdad police stations and the International Red Cross offices in the city, killing 43 people, all of them Iraqis. More than 100 are wounded in the attacks as well. The multiple, near simultaneous nature of the attacks mirrors al-Qaida attacks, but is attributed to Ansar al Islam and al-Zarqawi.
--Nov. 12, 2003
In an attack that punished both Iraqis who have volunteered to work with coalition forces and foreigners, 31 Iraqis and Italians are killed in a suicide bombing on the Italian Carabineri training center in Nassiriyah. Of the dead, 19 are Italian. Once again, Ansar al Islam is suspected in the attack, which leads to national mourning in Italy.
--Nov. 20, 2003
A suicide truck bomb explodes at the office of the Patriotic Union of Kurdistan, a U.S.-allied Kurdish political party in Kirkuk, killing four bystanders and wounding about 30 -- including children. No group claimed responsibility for the attack, but suspicion fell on Ansar al-Islam, a small, al-Qaida-linked Kurdish extremist group active in the northeastern area of Iraq that borders Iran. The day before, an Assyrian politician, also friendly to the United States, is kidnapped and assassinated near Basra, but U.S. officials are uncertain who killed him.
--Dec. 9, 2003
Suicide bombers, one in a car and another on foot, blow themselves up at the gates of two U.S. military bases, wounding 61 American soldiers but failing to inflict deadly casualties on the scale of other recent attacks in Iraq.
--Dec. 10, 2003
A U.S. soldier dies and 14 others are wounded when three suicide bombers attack the headquarters of the 82nd Airborne Division west of Baghdad in the city of Ramadi.
--Dec. 14, 2003
An attacker detonates a car bomb outside an Iraqi police station in Khaldiyah killing at least 17 people and wounding 33 others, hours before the announcement of Saddam Hussein's capture.
--Dec. 27, 2003
Five Bulgarian soldiers and two Thai soldiers are among 19 people killed and 18 injured in a coordinated attack on Coalition military bases in Karbala. The attackers strike a Bulgarian base in the north of the city, a compound containing the City Hall and police headquarters in the city center, as well as a multinational logistics base run by Polish, Thai, and American soldiers.
--Dec. 31, 2003
A car bomb detonates outside the Najil restaurant in the Karada district of Baghdad, killing at least five people and wounding 24, including three Americans. The hotel was a favorite of Westerners and the Iraqi upper middle class and was filled with New Year’s Eve revelers.
Jan. 14, 2004
A suicide bomber suspected of being from Ansar al Islam detonates a bomb outside an Iraqi police station, this time in Baquba. At least three Iraqis are killed and 29 wounded when a suicide bomber in a green civilian sedan targets the quick reaction police force.
--Jan. 18, 2003
A suicide bomber blows up a pickup truck packed with 1,000 pounds of explosives outside the headquarters of the U.S.-led coalition, killing 31 people — including two American soldiers — and injuring more than 60 — most of them Iraqis. Ansar is suspected.
Jan. 31, 2004
Nine Iraqis are killed and 44 wounded at a police station in Mosul by a suicide bomber driving a small car. Among those killed were two Iraqi policemen and seven civilians. Several policemen are among the wounded, including two lieutenant colonels, one major and one lieutenant.
--Feb. 1, 2004
In the worst suicide bombing since the attack on the Imam Ali Shrine in Najaf six months earlier, more than 100 people are killed and at least 200 are wounded in near simultaneous attacks on the headquarters of the two leading Kurdish parties, the Patriotic Union of Kurdistan and the Kurdish Democratic Party in Arbil. A former government minister, the deputy governor of Arbil province and the city's police chief are among those killed.
--Feb. 10, 2004
In Iskandariyah, south of Baghdad, 56 people are killed in a suicide bombing at an Iraqi police station. The bomb is carried in a red Toyota pickup and detonation is timed for when recruits are lining up to fill out applications. The attack, attributed to Ansar al Islam, is the third deadliest since the end of the war, but the second deadliest of the month.
--Feb. 11, 2004
In Baghdad, a suicide bomb explodes at an Iraqi Army recruiting station, killing 47, mostly recruits for the new Iraqi Army. The attack is almost identical to the attack the day before and brings the death toll for February to more than 200 people, the worst month since August. The U.S. links both bombings to Ansar al Islam and releases a 17-page memo by al-Zarqawi that calls for attacking "Iraqi troops, police and agents.” American officials note that the kind of attacks bear all the hallmarks of al-Qaida or affiliated terrorist groups.
--Feb. 15, 2004
In one of the boldest attacks yet in Iraq, Ansar al Islam launches a four-pronged attack on an Iraqi jail in Fallujah, killed 27 Iraqis, including police and others. The attackers shout "Allah Ahbar" as they move through the jail, indicating a fundamentalist bent. The fierce, well-coordinated daylight attack in Fallujah -- unprecedented in its scale -- raises questions whether Iraqi police and defense forces are ready to battle insurgents.
--Feb. 18, 2004
Two suicide bombers attack a Polish military barracks in Hillah, killing 11 Iraqis, but no coalition troops.
--Feb. 21, 2004
Thirteen people are killed and many others injured, when a suicide bomber rams an explosives-laden car into a police station in Kirkuk, northern Iraq. The blast, which happens in the Kurdish district of the city, takes place as the U.S. Defense Secretary, Donald Rumsfeld, visits Iraq to review the security situation on an unannounced visit.
--March 2, 2004
At least six bombs go off in Baghdad and Karbala, as Shiites celebrate the Ashura festival, killing 181 people, including at least 49 Iranian pilgrims. Many of the bombs are carried by suicide bombers among crowds of celebrants. The bombs are detonated simultaneously or near simultaneously in the two cities. The death toll is the second worst since Sept. 11, exceeded only by the Bali bombings. U.S. officials blame al-Zarqawi.
--March 17, 2004
A suicide bomber detonates a car bomb near the Hotel Lebanon in Baghdad, killing 16, including one Briton. The hotel is somewhat small, with less security than many of the larger hotels nearby. Many of the victims are Iraqi families who lived in the adjacent buildings.
--April 21, 2004
Terrorist bombs with all the hallmarks of al-Qaida explode in Basra and Az Zubayr in southern Iraq. The death toll is at least 68 dead with 200 injured.
--April 25, 2004
Three speed boats manned by suicide bombers try to attack Iraq’s main oil loading terminal in the Persian Gulf, doing minimal damage to the terminal but leaving two U.S. sailors dead.
--May 10, 2004
At least five people are killed at a crowded market in a western neighborhood of Baghdad.
--May 11, 2004
Nick Berg, a 26-year-old Philadelphia area business entrepreneur, is beheaded by al-Zarqawi in a video distributed on the internet. Berg apparently was captured on April 9 by one group who then sold him to Zarqawi’s Ansar al Islam. Berg is seen seated in front of a group of hooded men, one of whom, identified as al-Zarqawi, reads an “indictment” of Berg, then pulls out a knife and beheads him.
--May 17, 2004
The head of Iraq's U.S.-appointed Governing Council is killed in a car bomb blast near the headquarters of the U.S.-led coalition in Baghdad. Ezzedine Salim was near a checkpoint outside the compound when the bomb went off, killing him and several others.
--April 24, 2004
Al-Zarqawi claims responsibility for an attack on Khawr al-Amaya, an oil terminal near Basra
--Sept. 20, 2004
The militant group associated posts an Internet video of the beheading of U.S. civilian engineer Eugene Armstrong.
--Oct. 24, 2004
Al-Zarqawi, announces it carried out the killing of 50 members of the Iraqi National Guard found dead in eastern Iraq.
Compiled by NBC's Robert Windrem