Combat units report finding several weapons and explosives caches, along with car bombs and other homemade explosives.
Baghdad security officials said officers had defused another six potential car bombs, three of them in Sadr City.
But other parts of Afghanistan have been largely spared the daily drumbeat of car bombs, assassinations and whizzing rockets.
Military sources are quoted as saying that all the car bombs that have hit Algiers were manufactured in Ouled Allal.
Turkish President Abdullah Gul visited Reyhanli Thursday, when he vowed that those responsible for the car bombs would be held accountable.
At least 18 people have been killed and dozens injured by five car bombs in Shia-majority provinces of southern Iraq, officials say.
In the week before the bombing, Saudi security forces had claimed to have captured and defused no fewer than five similarly designed car bombs.
State-controlled al-Iraqiya TV said there were nine car bombs.
No matter how you slice and dice the numbers that are out there, whether you include, clearly sectarian car bombs and IED - improvised explosive devices - no matter what it is, it has come down by about two-thirds since December last year.
They were looking for a culprit of sorts: two weeks earlier car-bombs had exploded outside their embassies in Kenya and Tanzania.
Tony Ball, spokesman for the Secret Service, said the dog that alerted security officers to a suspicious car on the White House grounds Thursday morning was trained to detect bombs only.
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