Every time a bomb goes off in Iraq, an American convoy is attacked, or a coalition soldier is shot, the mystery deepens about who's behind the assaults.
President Bush on Sunday declared that "Iraq is now the central front" in America's war on terror, and US officials have for weeks said that hundreds, if not thousands, of Islamic militants are pouring into Iraq.
But while a recently seized document is reported to suggest that remnants of Saddam Hussein's Baath Party are "reaching out" to Islamic radicals, analysts say that such a marriage is far from being achieved.
"In the current security situation in Iraq, you could kill 20 Americans a day, easily, and it's not happening," says a senior Western official in Baghdad, who asked not to be named.
"An unholy alliance may happen, but the Baathists are terrified," the Western official says. "If they get out of their box and create links between [Hussein powerbase] Tikrit, Basra, and Baghdad, they know they will be found out much easier."
Still, anti-American forces have been busy, underscoring the daily risk faced by Anglo-American occupation forces in Iraq.
On Tuesday evening, a suicide bomber in the northern city of Arbil killed himself and an Iraqi child and wounded more than 50 people, including six US Department of Defense personnel, Reuters reported. Local residents said that the target was a house that was being used by US intelligence agents. A military spokeswoman initially said it had been a "safe house" but later, military press officers would confirm only that a blast had taken place.
Within the past 30 days,massive car bombs have destroyed the Jordanian Embassy and United Nations headquarters in Baghdad, killed Iraq's most prominent Shiite Muslim cleric and more than 80 others beside a sacred shrine, and targeted Iraqi police headquarters.
Lower-profile events underscore the persistence of the threat.
In recent weeks, US forces have discovered several workshops for making remote-control and tripwire bombs known here as "improvised explosive devices," or IEDs.
In one workshop, coalition sources confirm, 100 IEDs - a primary means used by the resistance to target convoys - were discovered, wired up and ready to go. Under the Jamhuriya Bridge in downtown Baghdad, three IEDs fashioned from 155mm artillery rounds were discovered and defused. Experts suggest they were placed well enough to have destroyed this key link across the Tigris River, close to coalition headquarters.
Two bombs - one a car bomb, another a car with a bomb inside - were discovered three weeks ago on their way to the Palestine Hotel, the home of the international press corps in Baghdad during the war.
And on the eve of the funeral of Ayatollah Mohammed Bakr al-Hakim last week, Iraqi police stopped two more car bombs at checkpoints.
Officials of the US-led Coalition Provisional Authority (CPA) estimate that more than 20,000 tons of munitions have been destroyed in Iraq already, but that remaining arsenals - large quantities of which disappeared in the immediate aftermath of the US invasion - are "unbelievably" large. Postwar anti-US resistance has already taken more American lives than the invasion itself. A US soldier from the 1st Armored Division was killed Wednesday trying to detonate a roadside bomb in west Baghdad.
Most of the attacks on US-led coalition forces - which averaged 15 a day last week - are known to be the work of loyalist security and intelligence wings. These wings are thought to have devised a postwar plan to make Iraq ungovernable.
US forces have caught or killed 40 regime chiefs out of 55 in the deck of cards. But analysts say that the continued freedom of Hani Abd al-Latif Tilfah al-Tikriti - the king of hearts, and former director of the Special Security Organization - highlights the loyalist role in directing anti-US attacks.
Whether those secretive cells may be linking up with agents of Al Qaeda or other militants remains unclear. On Sunday, just days before the second anniversary of the Sept. 11 suicide attacks, an audiotape purported to be from Al Qaeda emerged, vowing fresh attacks on Americans "everywhere."
"God has opened the doors of jihad in Iraq and Palestine, so do not close them," the voice said, in the sixth taped warning claimed by Al Qaeda this year.
"Clearly there is a general focus on Iraq by Al Qaeda, but [the group] is being hammered in Saudi Arabia, decapitated in the Gulf, and is not firing on all cylinders," says Toby Dodge, an Iraq expert at the University of Warwick in England. "They don't have the kind of network like they had in Afghanistan, where militants were pushed on [from Pakistan] through Peshawar."
Another key problem is the deep ideological chasm that for years has separated the staunchly secular Baathists from the religiously motivated Al Qaeda. Despite the common goal of targeting America, overcoming such obstacles would take time.
It's "not easy to break into the tight Baathist clan and tribal system," says Mr. Dodge. "Just rocking up in Tikrit with a beard and saying, 'Hi, fellows,' doesn't work. Freelancing Saudis are not welcome...so it's going to be slow to take off."
Some organizations suggest that signs of a Baath-Al Qaeda marriage first became visible during the UN bombing of Aug. 19, in which the UN chief in Iraq, Sergio Vieira de Mello, was killed along with 21 others.
"We're sure that that the UN bomb was a combination of foreign and Iraqi terrorists," says Zaab Sethna, a senior adviser to Ahmed Chalabi, a former opposition leader and current president of the US-appointed National Governing Council.
Mr. Chalabi's Iraqi National Congress organization has made some intelligence claims in the past that did not prove true - and funneled some Iraqi defectors before the war to the Pentagon, who provided still-unconfirmed data on weapons programs. Still, the INC runs one of the largest networks in Iraq in an ongoing intelligence operation funded largely, for the past year, by the Pentagon.
Mr. Sethna says the UN bombing was a case study, in which former Iraqi intelligence agents were able to provide detailed information on the UN headquarters, and inconspicuously "move foreigners around" to carry out the attack.
"The foreigners bring people who are willing to blow themselves up," says Sethna. "They also bring some specific bombmaking skills, such as shaping it to make it a directional blast."
Some argue that, while Iraqis are not predisposed to suicide missions, some local militants before and after the war made clear - in an echo of Palestinian suicide bombers - that they would give their lives to end occupation. Linking up with outside militants, though, may be a different matter.
"Jihadis [are] coming to Iraq, but if you look at the Al Qaeda rap sheet, they used the networks formed in camps in Afghanistan, and then went home," Dodge says. "Very, very few Iraqis were there. Baghdad is now a scary place and a permissive atmosphere, but not a supportive atmosphere. [Al Qaeda] must build these networks from the ground up."
Dodge gives an example of the fluid dynamic. During a postwar visit to Iraq, he says one militant told him that his group of 60, which had come from Jordan before the war to fight alongside Iraqi forces, was gone. Twenty had died, and 40 had gone home for good.