Answering Osama bin Laden's call for holy war in Iraq, hundreds of followers from at least eight nations have entered the country and are playing a major role in attacking Western targets and Iraqi civilians, U.S. and Iraqi officials say.
Operatives of the Al Qaeda terrorist network and affiliated extremist groups are collaborating with Saddam Hussein loyalists, officials say, forming an array of shadowy alliances that are emerging as one of the biggest challenges to U.S.-led efforts to bring stability to the war-torn country.
Some officials believe that Iraq is replacing Afghanistan as the global center of Islamic jihad and becoming the prime locale for extremist Muslim fighters who are eager to confront Americans on Arab soil.
As many as 2,000 Muslim fighters from as far as Sudan, Algeria and Afghanistan are operating in Iraq, officials say. Ansar al Islam, an Iraqi group that was previously active in northern Iraq, also has made a comeback, officials say. The Bush administration says Ansar has ties to Al Qaeda.
Although many of the foreign militants likely operate in small cells independent of any central command, others appear to have hooked up with Hussein loyalists who provide money, materiel and logistical support. In exchange, the foreigners provide suicide bombers and experience in guerrilla tactics.
While authorities have acknowledged the presence of some of the fighters, the role they are playing in the anti-American insurgency appears to be increasing -- and their unconventional tactics make them a formidable force. Foreign fighters are suspected of taking part in as many as a dozen suicide bombings that have killed more than 200 people in the last three months, including four nearly simultaneous attacks in Baghdad on Oct. 27.
"Since mid-July we have seen the reconstitution of Ansar al Islam and Al Qaeda," L. Paul Bremer III, the head of the U.S.-led civilian administration, said at a briefing of visiting Americans last week. "They are coming back into Iraq."
Jalal Talabani, the current president of Iraq's Governing Council, estimates that 500 to 2,000 Islamic militants from foreign countries are operating in Iraq, including some who may have arrived before the war started. Some officials of the U.S.-led coalition cite the same figure.
The largest group of militants is from neighboring Syria, officials say, while others have come from Jordan, Egypt, Yemen, Saudi Arabia, Kuwait and the Palestinian territories.
"The big majority of those criminals who are committing terror actions are from Al Qaeda" and associated militant Muslim organizations, Talabani said. "Those who are making suicide attacks are from Islamic fundamentalist groups."
Before the war, President Bush contended that Al Qaeda was active in Iraq. But it was not until several months after the U.S.-led occupation began that Islamic extremists apparently took advantage of the postwar chaos and started launching terrorist attacks.
U.S. officials acknowledge that they are hobbled in their efforts to stem the apparent surge in Islamic extremism because they have little information about the attackers or their activities.
Authorities believe that some of the fighters are Al Qaeda operatives and others are members of extremist groups affiliated with the network. Officials suspect that the groups operate as independent cells but are cooperating to some degree with one another and with Hussein loyalists seeking to regain power.
In September, Bremer told reporters in Washington that 248 foreign fighters had been arrested in Iraq, including 19 suspected Al Qaeda members. It is unclear when the arrests took place.
Bin Laden, who was critical of Hussein while he was in power, has repeatedly called on Muslims to go to Iraq and avenge the U.S. invasion.
"God knows if I could find a way to your field, I wouldn't stall," a voice identified as Bin Laden's said in an audiotape released in mid-October. "You my brother fighters in Iraq ... I tell you: You are God's soldiers and the arrows of Islam, and the first line of defense for this [Muslim] nation today."
It is difficult to gauge the extent of ties between Hussein loyalists and the foreign fighters. Some officials believe that a new alliance between Al Qaeda-trained foreigners and former agents of the Mukhabarat, Hussein's intelligence service, is behind some of the terrorist attacks.
"They are now fully operational and clandestine and working with terrorist groups to start hitting targets," said Iyad Allawi, a member of the Governing Council and its security committee. "They are getting more clever, and we will see more attacks in the weeks ahead."
In the battle against the U.S. presence in Iraq, the foreign fighters bring with them experience as guerrilla warriors who are skilled in reconnaissance and mounting surprise attacks while keeping a low profile.
The Hussein loyalists can offer their knowledge of local targets and the location of caches of weapons that could be used to make bombs. Top Iraqi operatives can contribute cash, much of it stolen shortly before or during the war.
The Iraqi insurgents may also be in contact with sympathizers who work near American or international targets. It appears, for instance, that some of the Iraqis working at the United Nations at the time of the August bombing of its headquarters in Baghdad had worked there during Hussein's regime.
Allawi said recent intelligence indicated that former Mukhabarat agents and Al Qaeda or its affiliates were forming a "field command" that would be responsible for operations against Americans and their supporters.
According to these reports, attacks would increasingly target the Americans and British, the leading members of the coalition that ousted Hussein, he said.
U.S. officials say there are an average of 29 attacks a day on coalition forces, most of them low-level incidents apparently staged by Hussein supporters. Some major attacks also appear to be the work of Hussein loyalists, including the downing of a Chinook helicopter near the town of Fallouja on Nov. 2 that killed 16 people and the shelling of Baghdad's Rashid Hotel on Oct. 26, which killed one and injured at least seven.
But other attacks bear the stamp of Al Qaeda: in particular, suicide car bombings of targets that are carefully selected for maximum psychological effect and to inflict a large number of casualties.
"The goal in hitting these targets is to create chaos, especially in Baghdad," Allawi said.
Authorities were able to establish the role of foreign extremists in the Oct. 27 bombings when police foiled a planned attack on a fourth Baghdad police station.
The would-be suicide bomber rammed a police barricade with his SUV, which was packed with explosives. The vehicle did not explode. When the man jumped out and threw a hand grenade at police, an officer shot and wounded him.
"Iraqis are traitors!" the attacker shouted at police, authorities say. "I am an Arab, you cowards! Allahu akbar [God is great]!"
Initially thought to be a Syrian, the would-be bomber was a Yemeni who entered the country through Syria, authorities say. He is believed to be in U.S. custody. There was no indication what he might have told investigators.
Ahmad Shyaa Barak, a member of the Governing Council who sits on its security committee, said authorities recently arrested another foreign militant who apparently was casing a building in Baghdad.
The man's passport showed that he had been to Afghanistan four times, including a six-month stay during which authorities suspect he attended an Al Qaeda training camp. He was turned over to coalition investigators.
"They captured him on the street," Barak said. "People were suspicious of him. He had a camera, and he was trying to take photos of a building that was a possible target."
In the last three months, Iraq has seen 13 vehicle bomb attacks. Most of them were suicide bombings, authorities say. The targets have included one of Iraq's holiest Shiite Muslim shrines, police stations, U.N. offices, U.S. facilities and the headquarters of the International Committee of the Red Cross. Most of the victims have been Iraqis.
Iraqi officials say the willingness to commit suicide and to target civilians are uncharacteristic of attacks by Hussein loyalists but are a common tactic for Islamic terrorists.
U.S. and Iraqi authorities as well as former agents of the Mukhabarat suspect that Islamic terrorists were involved in the deadliest attacks: the Aug. 19 car bombing of the U.N. headquarters in Baghdad that killed 22 people; the Aug. 29 bombing of the Imam Ali Mosque in Najaf that killed 120 people; the Oct. 12 bombing of the Baghdad Hotel that killed seven people; and the Oct. 27 attacks on the police stations and Red Cross that killed at least 35 people.
Two of the attacks may have been intended as assassinations of widely respected leaders who could have played a key role in stabilizing and reconstructing Iraq: the esteemed Shiite cleric Ayatollah Mohammed Bakr Hakim, who was killed in the Najaf bombing; and U.N. Special Representative Sergio Vieira de Mello, a strong advocate of handing over power to a new Iraqi government, who was killed in the U.N. headquarters blast.
Some officials fear that a growing Islamist movement in Iraq could give a boost to the extremist cause and train a new core of Muslim fighters, just as the war in Afghanistan against the Soviet Union did in the 1980s.
A senior U.S. intelligence official in Washington said Iraq has emerged as the focal point for Islamic jihad, becoming the most active front in the movement and the top priority for Muslim fighters who want to confront the United States.
The assessment, shared by analysts at the CIA and other agencies, underscores how in a matter of months Iraq has supplanted Afghanistan, Chechnya and other international trouble spots as the focus of the jihad cause.
"The fact that the U.S. military is there in force, that this is a core Arab state, that [the U.S. occupation] has been the biggest issue in world affairs in the last few months all add up to it being a highly important, highly active place" for jihadis, the official said, speaking on condition of anonymity.
Iraq is a top priority for jihadis in the Arab world, who have chafed at the presence of American troops in places such as Saudi Arabia for years but now confront the U.S. occupation of a nation in the heart of their region.
Asked whether Iraq was now the primary destination for Islamic fighters, the official said: "Far and away, no question about it."
He added that Iraq had earned that distinction because of its "size, prominence, importance and number of Americans to shoot at."
Although many in the West have been skeptical of Bush's contention that there was an alliance between Hussein and Islamic extremists, members of the Governing Council say the dictator began reaching out to the militants more than two years ago.
Before the war, hundreds of Ansar al Islam militants were trained at camps in northern Iraq and hundreds of foreign fighters were trained at camps outside Baghdad, said Talabani, the Governing Council president.
The Mukhabarat began forging ties with Arab extremists in 2001, Allawi said.
During the war, at least 5,000 foreign fighters came from abroad to aid the regime, Iraqi officials estimate. Many entered through Syria, where buses would fill up in Damascus with Syrians, Palestinians, Jordanians and occasionally Moroccans and Tunisians, according to injured fighters interviewed in Damascus, the Syrian capital, after their return. There is no estimate of how many fighters stayed behind after the war ended.
With the U.S. occupation, Iraq no longer had border guards, creating opportunities for militants to enter. The crossings opened up, and people streamed freely into Iraq.
"I'm afraid to say, it is going to get worse before it gets better," Allawi said. "They are an evil group. They are looking at Iraq as their haven and as the staging post to hit at every decent and civilized target."
Paddock and Rubin reported from Baghdad, and Miller from Washington.