With the US-led coalition handing back sovereignty in barely two weeks, daily car bombings and assassinations have saddled Iraq with an insurgency now at its most dangerous and unpredictable, with no end in sight.
Sixteen people were killed Monday when a suicide car bomb exploded by Baghdad's packed Sadoun Street in the second such attack in less than 24 hours, as officials warned of greater bloodshed ahead of the sovereignty transfer.
David Gompert, US overseer Paul Bremer's top advisor on Iraq's national security, warned there was no clear cut military victory on the horizon and said the coalition and Iraq would have to weather the bad times.
"It's going to be a while. The terrorists are hardened. They are professionals," he said, looking to the January national elections as a key date in winning legitimacy for Iraq's post-Saddam Hussein political order.
He said the insurgency would die out only when people looked to the Iraqi government as their own and backed the coalition-led security forces in fighting the rebels. He added an effective Iraqi security force was one year away.
With a legitimate government, "people will be more inclined to not only reject but to help apprehend and keep out these shadowy and sophisticated enemies," he said.
The new interim Iraqi government, installed June 1 by the coalition, the United Nations and the US-imposed Governing Council, was a step in that direction, but there is a long road ahead.
"It takes months and months before you've got that combination of effective forces and popular support... in the meantime there is no sign the professional terrorists and the hardened Saddamists will stop."
Saddam's former security services and foreign fighters, primarily linked to Osama bin Laden's Al-Qaeda network, have already taken advantage of the coalition's difficulties to dig deeper inside Iraq, Gompert said.
Al-Qaeda militants have developed effective networks that allow them to move and carry out their attacks, with little chance of detection.
"I would simply say they are finding it no more difficult to get in the country. They have established an ability to operate in the country and move throughout the country. Over time, they have improved that capability," Gompert said.
"And they are increasing the use of suicide bombs which is probably the most effective weapon available to them at moments like this because of the... terror it strikes in people's minds."
Gompert warned one Al-Qaeda aim was to recruit Iraqis to carry out suicide bombings and was unable to rule out the possibility that it had already happened.
"If you give them time, because they are good at planning and organising they will bring to bear additional expertise - funding, people, explosives experts, methods of suicide bombing.
"So we are dealing with a more difficult international terrorist threat today too than we were six months ago."
For its part, the strength of Saddam's old security agents, estimated in the few thousands, has only confounded the coalition.
Last December, when Saddam was captured, Gompert predicted a low-level resistance from the elite of the old regime.
Instead, "the Saddamist insurgency has become more sophisticated, more difficult to defeat militarily because it does not have a head."
The capture of Saddam and 43 others on the coalition's list of the 55 most-wanted old regime officials liberated seasoned henchmen of the jailed leader's intelligence service, special republican guards and other units.
"The old Saddam security organisation wasn't very effective, they were ruthless and brutal, but not especially capable," Gompert said.
"If you take away the head, which is what happened as the deck of cards was collected, what's left is a distributed collection of killers and executioners and the like who by virtue of becoming more autonomous and self-sufficient are more difficult to locate."
Iraq's new interim government, reacted quickly Monday to quell people's anger after the latest bombing.
Prime minister Iyad Allawi warned Iraqis that militants were trying to discredit the new regime.
"They are trying to defer the process of handing over sovereignty to the Iraqis by the 30th of June," Allawi told reporters.
Similar pronouncements were delivered Sunday by Iraq's new president Sheikh Ghazi al-Yawar, US Secretary of State Colin Powell and US national security advisor Condoleezza Rice.
Yawar, president of Iraq's interim government, warned in an interview with NBC television of a "terrible" time ahead before security could be restored.
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