The U.S. military in Iraq says it has identified several groups loyal to Saddam Hussein's Baath Party, which may be behind the upsurge of attacks against coalition forces in recent weeks. The coalition is gearing up to face the growing violence.

Last July, when U.S. troops in Iraq were being attacked an average of 15 times a day, the country's top U.S. administrator, Paul Bremer, said he believed most of the attacks were being planned and carried out by loyal members of Saddam Hussein's former Baathist regime. "The attacks, which lead to casualties and confrontations, are attacks being conducted by, we believe, ex-military or intelligence people, professionals. They are being conducted on a professional basis," he said.

Four months later, the attacks have become more frequent, more effective and better coordinated. A spokesman for coalition forces, U.S. Army Brigadier General Mark Kimmitt, explained why the Baathists are blamed for most attacks. "They are ones who profited from the former Saddam regime, profited from the dictatorship, will not win out in a democratic and free Iraq, and they have everything to lose [due to] human rights, human dignity, democracy, and independence in this country," he said.

Commanders here say, what has changed during the past few months is that Saddam loyalists now appear to have a structure for resisting the coalition occupation of Iraq, organizing themselves into several distinct groups.

At the bottom level, commanders believe, are a number of neighborhood cells, each with more than two-dozen low-level Baathists who are angry over their sudden loss of status and income. They are believed to be carrying out the majority of the daily rocket-propelled grenade and small arms attacks against U.S. patrols and convoys.

At the next level, larger organizations of Baathists may be at work. One is known as the Return Party, a group composed primarily of senior military Baath party members. They are said to be supplying weapons and cash to criminal gangs and poor, unemployed Iraqis to plant roadside bombs and fire mortars and rockets at coalition targets.

The other Baathist group, Mohammed's Army, is much more shadowy, likely operating under the control of Saddam's former security services. In July, one alleged member of the organization told a Dubai-based newspaper that remnants of the Fedayeen, intelligence services and the Special Republican Guards had grouped together to study the tactics of Palestinian militant groups and the Lebanese militia, Hezbollah, during their war against the Israeli occupation of southern Lebanon.

Two weeks ago, Mohammed's Army claimed responsibility for the downing of a U.S. Army Chinook helicopter that killed 16 soldiers on November 2. Members of this group also are thought to be behind numerous assassinations of prominent Iraqis, who had been working with the U.S.-led coalition in efforts to rebuild Iraq.

The U.S. military believes all the Baathist groups are working to bring their party back into power. But the commander of U.S. troops in the restive Anbar province in central Iraq, Major General Charles Swannack, said it is not clear how closely the groups are coordinating their movements and activities. "I would guess, based upon my assessment, is that there is some loose [command and control] architecture, on a regional basis, directing some of the attacks. I do not have any evidence to suggest that, other than my instincts," he said.

In recent months, a number of suicide car bombings targeting Iraqi police, coalition forces and international humanitarian organizations have also raised the possibility that Baathists are linking up with Iraqi and foreign Islamic extremists to carry out major attacks.

The commander of U.S. forces in the Baghdad area, Brigadier General Martin Dempsey, said the American military is convinced that Baathists are involved in many of the suicide bombings. "We suspect that they decide to commit a sensational attack, one in which they are going to try and grab the headlines. I think they go outside to get a volunteer, a Jihadist, or call them what you want, a foreigner, to drive the car. But to the extent that that is an actual alliance, versus a simple matter of convenience, frankly, I do not know," he said.

Army Lieutenant Colonel James Danna said the main reason much remains murky about these opposition groups is that the U.S. military is just beginning to develop a network of reliable local informants. "We are designed to exploit electronic intelligence, imagery intelligence, and signals intelligence," he said. "We are not designed to exploit human intelligence. We had to build that capability here."

Facing mounting loss from escalating anti-coalition attacks, U.S. troops have redoubled their efforts to find Saddam Hussein. The commander of ground forces in Iraq, Lieutenant General Ricardo Sanchez says fear that Saddam will return to power is preventing many Iraqis from giving troops information vital to curbing the insurgency.