BAGHDAD — As the American military prepares to withdraw from Iraqi cities, Iraqi and American security officials say that jihadi and Baath militants are rejoining the fight in areas that are largely quiet now, regrouping as a smaller but still lethal insurgency.
There is much debate as to whether any new insurgency, at a time of relative calm in most of Iraq, could ever produce the levels of violence that existed at the height of the war. A recent series of attacks, however, suggests the danger, all the more perilous now because the American troops who helped to pacify Iraq are leaving.
Several well-planned bombings, one on a street recently reopened because it was thought to be safe, have killed 123 people, most of them in and around Baghdad. Three were suicide bombings, signatures of al-Qaida in Iraq, a homegrown Sunni extremist group with some foreign leadership.
Assassination attempts on members of the Awakening Councils, some of them former insurgents who switched sides for pay, are rising, as are fears that some Awakening members are joining Islamic extremists or other insurgent groups. On Saturday, an important Awakening leader was arrested on charges of being a member of the military wing of the outlawed Baath Party, formerly led by Saddam Hussein.
Detainees long held in American military custody are being set free every day, potentially increasing the insurgency's numbers. At least one has already blown himself up in a suicide attack.
Most of the latest attacks, at a time when overall violence is at its lowest since the beginning of the war in 2003, have singled out Iraqis, but one development affects the Americans. A new weapon has appeared in Iraq: Russian-made RKG-3 grenades, which weigh just 5 pounds and, attached to parachutes, can be lobbed by a teenager but can penetrate the American military's latest heavily armored vehicle, the MRAP. The grenades cost as little as $10., according to the military, which would not say how often they have killed soldiers.
To some experts, this amounts to ugly but unavoidable background noise, the deadly but no longer destabilizing face of violence in Iraq. In this view, there will be attacks, but such attacks will no longer be likely to topple Iraq's government.
Other officials, Iraqi and American, are more worried. They observe jihadi and other insurgent groups activating networks of sleeper cells that are already striking government and civilian targets. Insurgent groups linked to Saddam's rule are also reviving. Among the most powerful now is Nashqabandi, which has ties to a former Saddam deputy, Izzat Ibrahim al-Douri.
"Al-Qaida and the hard-core Saddamists are the main threats to the national security of Iraq," said Mowaffak al-Rubaie, Iraq's national security adviser.
"Nashqabandi is the cradle; they are providing logistical support for al-Qaida," he said. "What we are seeing is the resurgence of the hard-core Saddamists, but using al-Qaida in Iraq as a front and as suicide bombers."
American military officials believe they have checked the insurgency, but they liken it to a spring. "It can come up quickly as soon as it is released, but the longer you keep it down the less it rebounds," said Col. James Phelps, an insurgency expert attached to the multinational force in Iraq.
In interviews with 14 leaders of the Awakening movement, all said they believed that the jihadi presence in their areas had increased, as American troops began to close combat outposts or hand them over to the Iraqi army. The Awakening leaders reported signs of trouble: assassination attempts, homemade bombs placed near their homes or under their cars, leaflets urging them not to work with the Iraqi government.
"We notice when there is a bomb buried on a back road where there has not been one before," said Sheik Awad al-Harbousi, whose Awakening group works in Taji, north of Baghdad, much of it empty country traversed by rugged dirt roads. One of his fighters was killed three weeks ago.
Undermining the stability of the past few months is rising friction between the Awakening Councils and the Iraqi army and the police. The tensions turned violent in Baghdad on Saturday, when members of the Awakening Council in the Fadhil neighborhood of Baghdad had a shootout with a combined American and Iraqi force.
The Awakening Councils are largely Sunni, while the security forces are dominated by Shiites. Many Awakening members are angry because promises of jobs in the Shiite-dominated government have not been kept.
In Diyala province, the insurgency has never been fully eradicated, according to the American and Iraqi military. The province's geography favors those who know its dry high hills, empty patches of desert and thick groves of date palms.
Though the province is far more secure than in 2006 and 2007, when the provincial capital, Baqubah, was known locally as "the city of death," attacks are now increasing. Forty-three people were killed in Diyala in March, up from 29 in February and six in January, according to the Diyala Operations Command.
Ali Al-Tamimi, the chief of the Provincial Council's security committee, predicted an increase in violence both in Baghdad and in Baqubah because the security commanders have not acted on warnings about the growing activities of armed groups within an hour of Baghdad.
"We have told them that al-Qaida is still present in some neighborhoods and villages," he said. "They have not done enough to stop them."