BAGHDAD If Iraqis were hoping that the withdrawal of U.S. forces last year would finally mean the end of war, al Qaeda and its Sunni militant allies are determined to prove otherwise.
Daily bombings and shootings remain an endemic feature of life. In the past three months, al Qaeda-linked fighters have been blamed for attacks that have killed at least 250 people.
In a particularly poignant reminder of militants' potency this week, gunmen in unauthorized uniforms of special commandos drove from checkpoint to checkpoint in the western town of Haditha before dawn, gunning down police. They killed 27 including two officers dragged from their homes and slain in the street.
A return to the all-out sectarian slaughter that killed tens of thousands of Iraqis in 2006-07 is unlikely. Nor are al Qaeda fighters threatening to again impose their rule over whole swathes of Iraq as they did in the early years after the U.S. invasion that toppled Saddam Hussein.
But unlike Shi'ite militia groups - which have largely declared they are ready to lay down arms now that U.S. troops have left - al Qaeda and other Sunni groups have shown no sign of giving up the fight. And Iraq's security forces show little sign of the wherewithal to vanquish them once and for all.
Al Qaeda will continue to be a menace until security forces have better intelligence, are more technologically sophisticated and can gain the public's trust in those pockets where the militants still have support.
In the absence of American troops to oppose, al Qaeda and its allies in Iraq have hewed to explicitly sectarian rhetoric, calling on all Sunnis to join them in battle against the Shi'ite-led government in Baghdad.
"Know that the coming stage is a stage of real confrontation and war against the despicable (Shi'ites), whether you like it or not," the al Qaeda-affiliated Sunni group Islamic State of Iraq said after claiming responsibility for attacks on Iraqi security forces that killed 60 people on February 23.
Ibrahim al-Shimari, spokesman for the Islamic Army, another militant group, said it would keep fighting as long as "the effects" of the former U.S. occupation still exist.
"We are continuing to defend the Iraqi people and this weapon is the guarantee of the security of the Iraqi people."
Iraqi authorities insist they have the situation under control. Deputy Interior Minister Adnan al-Asadi says attacks have fallen by more than 80 percent compared to past years, with the remaining violence a sign of terrorist groups trying to "prove they are still on the scene".
"After the tightening that happened against al Qaeda and other groups and the heavy blows they received, the detentions of many leaders and members that contributed to cells breaking up, ... sanctuaries and sources of finance are much more restricted," Asadi told Reuters. "That has led these groups to, from time to time, prepare an attack to signify their identity."
Iraq's branch of al Qaeda is only loosely linked to the wider organization founded by Osama bin-Laden, but shares its strong anti-Western ideology and its aim of restoring the strict Sunni Muslim caliphate that ruled the mediaeval Arab world.
In the early years after the fall of Saddam, al Qaeda fighters took control of cities and towns in Sunni-dominated western and central Iraq, resisting the U.S. presence and imposing a stark interpretation of Islamic law.
They also fought Shi'ites, who make up the majority in Iraq but are denounced by al Qaeda as apostates from true Islam.
Eventually al Qaeda's extreme violence and rigid rule alienated Sunni tribes, who teamed up with U.S. troops to drive them out, first from their stronghold in Anbar province and then from other areas. Since 2008 the fighters have no longer controlled significant territory.
Having fought to drive the militants out, Iraqi villages and towns are unlikely to welcome al Qaeda back, Asadi said.
"Al Qaeda will not return to take over any province, including Anbar, because the people of Anbar have tasted the bitterness of al Qaeda," Asadi said.
But cells remain, carrying out suicide bombings and shooting attacks on a daily basis. Mostly they have struck vulnerable security forces targets, such as police checkpoints.
"They will punish security forces for supporting the government and use violence as a way to highlight that," said Brian Fishman, a research fellow with the Combating Terrorism Center at the U.S. Army's academy at West Point.
This year, al Qaeda has also drawn strength from anger over the conflict in neighboring Syria, where a mostly Sunni population has risen up against President Bashar al-Assad, whose Alawite sect is an offshoot of Shi'ite Islam.
"It's a real opportunity for al Qaeda in Iraq because the sectarian dynamic in Syria works to their advantage," Fishman said. Bin Laden's successor as global al Qaeda leader, Ayman al-Zawahri, has called on Sunnis to support the rebels in Syria.
Iraqi troops privately say a lack of intelligence-gathering capability is their biggest hurdle in combating al Qaeda. Without the ability to deeply analyze information, they have little choice but to mount raids as soon as tips come in.
"We don't have the technology or the experience," said Adnan, a veteran soldier who joined the army in 2003 after the fall of Saddam. He did not give his full name because he was not authorized to speak to the media.
"Now, whenever we get any information we act on it. We raid, we ambush. We don't delay, we don't check to see the validity of the information," he said.
With low pay in a stressful job, the security forces are susceptible to infiltration by militants.
"The biggest weakness is that of a soldier who is in cahoots with them. They exploit him and tell him to keep quiet about attacks," said Adnan.
The security forces are vast and decentralized, and training is inconsistent. Units each have their own operating procedures and dress themselves in an array of non-standard uniforms that can be bought in any street market, which makes it easy for militants to pose as members of the security forces.
Some checkpoints stop cars and search them. At others, policemen can be spotted leaning against lightpoles, smoking cigarettes and waving cars through with barely a glance.
John Drake, senior risk consultant with security firm AKE Group, said the security forces' own reputation for corruption and brutality had cost them the trust of the public which is vital for setting up a good intelligence operation.
"The general community in many of the most hazardous areas in Iraq do not trust the police forces. Officers in the past have been involved in kidnap and extortion and it is going to take a long time for public trust to return," he said.
"Until then, the people will not provide them with information on suspicious activity. They will not provide them with warnings of potential infiltration of militants."
(Reporting and writing by Yara Bayoumy; Editing by Peter Graff)