Amid a spate of deadly attacks, U.S. military officials in Iraq are racing to determine the identity of the insurgents behind several suicide bombings, which killed dozens of people and wounded hundreds. Military commanders on the ground believe Islamic militant fighters from neighboring countries are primarily responsible for the attacks.
As the Islamic holy month of Ramadan began in Iraq on Monday, suicide bombers struck the Baghdad headquarters of the International Committee of the Red Cross and three Iraqi police stations in coordinated attacks that stunned the nation.
Four days later, a London-based Arab magazine acknowledged that one of its reporters had received an e-mail from an alleged al-Qaida leader more than a week ago, warning that the terrorist network was planning to carry out attacks against Americans during Ramadan.
Top U.S. officials and military commanders are still not saying whether they believe al-Qaida was behind Monday's car bombings. It is still unclear who carried out the deadly car bombings that ripped through the United Nations headquarters, the Jordanian and Turkish embassies, and the Baghdad Hotel in recent months.
But the U.S. military here in Baghdad says the level of organization and the scale of the attacks suggest that well-trained fighters with ties to Islamic militant groups are responsible.
U.S. Army Colonel Ralph Baker commands the Second Brigade of the First Armored Division, which is in charge of security for most of Baghdad and its suburbs.
Colonel Baker said it is possible that former intelligence service members of ousted Iraqi leader Saddam Hussein's regime could have made the car bombs and ordered the attacks.
But based on seven months of experience battling Saddam loyalists in the streets of Baghdad, he does not believe Iraqis would carry out suicide bombings that could inflict heavy casualties on their own people.
"Typically, the regime loyalists are going to minimize injury to Iraqi citizens, because their fight is with coalition forces, not Iraqi citizens for the most part. When you start to see targets that include Iraqis, then you can start to suspect international terrorism as a culprit. Iraqis will tell you that, 'that is simply not the way we do things.' They're just not culturally disposed to suicide bombings," Mr. Baker said.
As early as August, the U.S. administrator in Iraq, Paul Bremer, had warned that hundreds of militant foreign fighters - mostly from Syria, Iran, Saudi Arabia and Yemen - had entered Iraq.
Some of the fighters, he says, are members of Ansar al-Islam, a militant group believed to have links to al-Qaida. Ansar's base in northeastern Iraq was destroyed by coalition forces early in the war. But U.S. officials believe the organization has regrouped in neighboring Iran, and has re-entered Iraq.
On Friday, The New York Times cited senior U.S. officials as saying that Saddam, who is still in hiding with a $25 million bounty on his head, may be playing a role in coordinating bombings and attacks against coalition troops. The report said Saddam is believed to have recently met with a high-ranking aide, who has been in contact with Ansar al-Islam.
Second Brigade's executive officer, Lieutenant Colonel Jim Danna, said he has not seen any evidence so far that suggests Saddam is linking up with terrorist groups. "I think there is a natural tendency for those two forces to work together, even though they don't have the same ideological outlook. The enemy of my enemy is my friend. Therefore, those two together could make some linkages and have some more unity of effort. Do we see that happening? I have no evidence of that right now," Col. Danna said. The threat of more violence by militant groups in Iraq is an enormous concern to coalition forces, who have had mixed results in their seven month-long effort to bring stability to the country.
Some military units have had success convincing Iraqi civilians in their neighborhoods to come forward and provide intelligence. Commanders say many of these tips have led to numerous arrests and stockpiles of weapons. Consequently, attacks against coalition troops in those areas have dropped.
But in other areas of Iraq, especially in the so-called Sunni Triangle, attacks have become more frequent. The triangle is a Sunni Muslim-dominated area north and west of Baghdad, where support for Saddam remains strong.
U.S. military officials say they believe 95 percent of all attacks in Iraq are being perpetrated by Saddam loyalists. The officials said they remain optimistic that the intelligence network they are building in Iraq will be good enough to eventually capture Saddam and defeat his followers.
But Colonel Baker said building an intelligence network that can detect and disrupt terrorist activities is posing a new challenge for the coalition. "The trick is, how do we alert ourselves to their activities, and get as good a indication on what they're going to do, as we have on the former regime loyalists right now? All I can tell you is that we're adapting to that threat," Mr. Baker said.
Coalition forces are believed to be holding more than 250 non-Iraqi fighters in Iraq. The U.S. administrator, Mr. Bremer, said he views the presence of terrorist fighters, not Saddam loyalists, as the biggest obstacle to the peaceful reconstruction of the country.