BAGHDAD The U.S. military said on Thursday it was setting a trap to "eliminate" al Qaeda militants around Baghdad, but also said 12 American soldiers had been killed in the past two days, mostly in roadside bombings.
The toll of civilian casualties continued to rise after a suicide bomber killed 16 people by ramming his truck into a government building near the northern city of Kirkuk.
Tens of thousands of U.S. and Iraqi soldiers are pushing on with simultaneous operations in Baghdad and to the north, south and west of the capital under Operation Phantom Thunder, a new plan aimed at rooting out al Qaeda fighters and other militants.
The latest offensive comes after the U.S. military completed the build-up of its forces in Iraq to 156,000 soldiers and aimed to deny militants sanctuary in the farmlands and towns surrounding Baghdad.
"To the extent that you can eliminate them, we will," said U.S. military spokesman Rear Admiral Mark Fox.
"(And) if you've got it properly cordoned then they're going to flee into somebody's arms. It's a trap."
Hard fighting was expected in the next 45-60 days, he said.
In the worst incident for the military in the past 48 hours, five soldiers were killed when a roadside bomb hit their vehicle in northeastern Baghdad on Thursday. Three Iraqi civilians and an Iraqi interpreter also died.
Another roadside bomb killed four U.S. soldiers in west Baghdad on Wednesday. Such bombs are by far the biggest killers of U.S. forces in Iraq.
Washington and U.S. commanders say that some of the most sophisticated roadside bombs -- "explosively formed penetrators", or EFPs -- are still being brought in to Iraq from neighboring Iran, a charge Tehran denies.
"I know that inside of my battle space, there are munitions clearly marked with Iranian markings, and I am losing many of my soldiers to EFPs," Major-General Rick Lynch, whose command stretches south from Baghdad to the Euphrates River and west to the Iranian border, told Reuters in an interview.
A total of 3,545 U.S. soldiers have been killed since the start of the unpopular war in March 2003.
On Baghdad's southern flank, the military said 60 suspected insurgents were detained, 17 boats used to transport bomb parts to the capital were destroyed, and weapons caches were seized.
To the north, 10,000 U.S. and Iraqi troops continued assaulting al Qaeda hideouts in an operation focused on Baquba, the volatile capital of Diyala province, that has killed 41 militants over the past three days, the U.S. military said.
Fox said it was too early to call Operation Phantom Thunder a turning point in the war but said the military was stepping up the pressure on al Qaeda.
"This is a military operation with clear objectives ... to set the conditions for the political and economic progress that the government of Iraq needs to demonstrate," Fox said.
U.S. President George W. Bush has sent 28,000 extra soldiers to help curb sectarian bloodshed and buy Shi'ite Prime Minister Nuri al-Maliki time to reach a political accommodation with disaffected minority Sunni Arabs, who are locked in a withering cycle of violence with majority Shi'ite Muslims.
The key element of political goals set by Washington, an oil law, advanced on Thursday after Kurdish officials from autonomous Kurdistan said they had reached agreement with the central government on sharing oil revenues.
Under the agreement, the Kurdistan region will take 17 percent of all oil revenue from Iraq's oil fields, the world's third largest. But there is still a dispute over who will control the fields.
In Sulaiman Bek, a town south of Kirkuk, a suicide truck bomber struck a compound housing the municipal headquarters and local town council. The blast reduced nearby houses to rubble.
Police and hospital sources said 16 people were killed and 76 wounded. At least 10 city council members, including the mayor and the police chief, were among the wounded.
(Additional reporting by Dean Yates, Waleed Ibrahim and Ross Colvin in Baghdad)