At least 18 people were killed Tuesday in five car bomb attacks targeting police in the northern oil city of Kirkuk as violence raged country-wide after the death of Abu Musab al-Zarqawi.
Al Qaeda in Iraq said it had chosen a new leader, Abu Hamza al-Muhajer, an Egyptian, and promised to continue the work of slain militant leader, in an Internet statement.
It decided to "prepare, in coordination with the other components of the consultative council of the mujahedeen, great operations that will shake the enemy", the statement said.
US military leaders in Iraq said they had been expecting renewed attacks in the wake of Zarqawi's death while security measures in Baghdad were being beefed up in anticipation of Prime Minister Nuri al-Maliki's long awaited new security plan for the capital.
The attacks came after the first of two days of high-level talks US President George W. Bush held with top diplomatic and military officials to reassess the war effort in Iraq focusing on greater security responsibility for the Iraqi government.
"The best way to win this war against an insurgency is to stand up a unity government which is capable of defending itself but also providing tangible benefits to the people," he said at the Camp David retreat in Maryland.
US troops, however, would not be drawn down until conditions improve on the ground and the Iraqi security forces can clearly secure the situation.
The five car bombs, several of them suicide bombs, in Kirkuk hit an ethnically diverse city that has not been known for large car bombs, but rather mostly individual assassinations between ethnic and sectarian groups.
"The total casualties for the five car bombs are 18 killed and more than 45 wounded," said Brigadier General Burhan Hamid Tayyib, police chief for Kirkuk center.
Another suicide car bomb attempt in central Kirkuk targeting headquarters of the PUK party was foiled when guards shot dead the driver of a booby-trapped car as he drove towards them, without detonating the car.
The first car bomb exploded at around 7:30 am (0330 GMT) in the city's Tisaeen market in an area largely inhabited by Shiite members of the city's Turkmen community, killing 13 people, including two policemen, and wounding 18.
Approximately half an hour later, a suicide car bomb attempted to ram the main police headquarters, prompting police to open fire on it. The car exploded, missing its target, police commander Major General Torhan Yussef, but two policemen died and eight civilians were wounded.
The three other car bombs, one of which was a suicide attack, exploded in different parts of the city, killing three more policemen and wounding over a dozen, including Colonel Taher Salah al-Din, the police chief for the southern Kirkuk Hurriyah neighborhood.
The bombing campaign comes after the arrest of eight suspected insurgents by US and Iraqi forces in two operations on Sunday in Kirkuk.
On Wednesday, the US military dropped a pair of 500 pound bombs on Zarqawi's safe house, killing him and yielding a "treasure trove" of intelligence about the organization.
In Baghdad, there were a number of attacks, including a bomb targeting a police patrol in central Baghdad that killed one policemen and wounded four others, as well as injuring a detainee they were transporting.
A professor at the College of Engineering was shot dead as he left his house and 14 bodies, shot and bearing signs of torture, were found in and around the city.
In Karbala, gunmen shot dead a police captain in the criminal investigations department.
A bomb targeting a police patrol in the Samarra market missed its target but killed four civilians and injured seven.
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