Brig. Amer Ali Nayef, the second-ranking police officer in the war-torn capital, and his son Lt. Khalid Amer were gunned down while traveling in a car on their way to work.
The group headed by al-Qaida ally Abu Musad al-Zarqawi claimed responsibility for the assassination in a statement posted on an Islamist Web site.
"Al-Qaida Organization of Holy War in Iraq carried out the operation to assassinate the deputy police chief of the Jews and crusaders, Amer Nayef, and his son who is a soldier in the pagan (national) guards," the group said in the statement.
Hours after the shooting a massive roadside bomb exploded as an American patrol passed, destroying a heavily armored Bradley Fighting Vehicle and killing two American soldiers.
The attack, which also wounded four other Americans, is seen as part of a stepped up effort by insurgents to plant more powerful bombs in hopes of piercing the armored vehicles. Seven U.S. troops were killed last week when a roadside bomb in Baghdad destroyed their Bradley vehicle.
Monday's violence followed a weekend of attacks and accidents that killed scores of Iraqis and coalition soldiers.
A deadly incident at a weapons dump Sunday also threatened to push one of the coalition of nations out of Iraq. A massive explosion at a site some 40 miles southwest of Baghdad killed eight Ukrainian soldiers and one Kazakh.
Although initially reported as an accident that occurred while the soldiers were preparing old aircraft bombs for demolition, Ukrainian officials said Monday they believed the explosion may have been part of an insurgent attack.
"It's a preliminary scenario, but this might have been a pre-planned action," a spokesman for the Ukrainian defense ministry told Reuters, adding fragments of an explosive device were found at the site.
An insurgent group called the Islamic Army of Iraq claimed responsibility for the explosion that wounded an additional 11 soldiers -- seven Ukrainians and four Kazakhs.
In response to the explosion, outgoing Ukrainian President Leonid Kuchma said he had ordered his military advisers to draft plans for a full withdrawal of his nation's 1,600 troops in the first half of 2005, Reuters reported Monday.
Ukraine's incoming, pro-western president Viktor Yushchenko released a statement Monday saying he would also bring home the soldiers. Ukraine's contingent is the fourth largest foreign force in Iraq.
"As is well known, the withdrawal of the Ukrainian peacekeeping force is one of our priorities. Yushchenko will address it immediately after he takes the post of president," the statement on Yushchenko's Web site said.
The explosion at the weapons site came on a day of deadly accidents involving American soldiers.
U.S. official acknowledged accidentally dropping a 500-pound bomb on the wrong house in the northern village of Aaytha. American military sources said five civilians died in the attack, but local residents said 14 had died and showed reporters 14 freshly dug graves.
Hours later, U.S. troops opened fire near a checkpoint south of Baghdad after their convoy was hit by a roadside bomb. A local hospital official said at least eight people, including two Iraqi police officers had died in the melee.
In other violence Sunday, a U.S. soldier died in a roadside bombing in Baghdad, while a Marine was killed in action in the restive Anbar Province.
The violence has intensified ahead of planned Jan. 30 elections. Many Sunni Muslims have called for a boycott to protest ongoing attacks.
Despite the insurgency, the United Nations adviser for elections said Sunday that the balloting should go on as scheduled. Carlos Valenzuela said Iraq's Independent Electoral Commission would only recommend a delay if it was the political consensus of the major parties and Iraqi officials.
"So far, electoral preparations are on track. That's why the Electoral Commission feels that there is no reason to stop the elections, to postpone the elections, to delay the elections," he told Reuters in Baghdad.
"The law makes absolutely no provisions for delaying the elections and you will have a major constitutional crisis if you don't have the elections because there is no consensus about delaying."
In an effort to bolster participation among Sunnis, American Embassy officials met over the weekend with an influential group of Sunni clerics.
According to the embassy, the clerics offered to lift the boycott if the United States set a timetable for a withdrawal of troops from Iraq.
"That was their offer to us," said U.S. Embassy spokesman Bob Callahan. "We have no intention to establish a timeline for withdrawal from Iraq at present. The Iraqi government agrees."