Husein al-Zubaidi, a Diyala official, said: "Al-Qaeda cheated people under the name of 'jihad' and their actions were against all principles.
"They hurt all Iraqi sects, this is what pushed the national armed groups to face them strongly and bravely."
Former Sunni fighters on Saturday asked the US to stay away, then ambushed members of al-Qaeda in Iraq, killing 18 in a battle that raged for hours north of Baghdad, a former Sunni group leader and Iraqi police said.
Abu Ibrahim, a senior Islamic Army leader, said on Saturday that his fighters killed 18 al-Qaeda fighters and captured 16 in the fight southeast of Samarra, a mostly Sunni city about 90km north of Baghdad.
The most notable sign of shifting alliances has been that of tribal chiefs from Anbar, Iraq's largest Sunni province, joining with the government to fight al-Qaeda.
There are also reports that armed groups once allied to al-Qaeda have started to turn against them.
In a sign the government is working towards reconciliation, 70 former members of Saddam Hussein's party were reinstated to their jobs after they joined the fight against al-Qaida in Anbar, Ali al-Lami, a senior official with the commission that considered their cases, said.
Al-Lami told the Associated Press news agency that the former Baath party members included 12 university professors, officers in the disbanded Iraqi army, former policemen and teachers.
According to a US military commander in Baghdad's southern areas, al-Qaeda is losing ground.
"Iraq is still under foreign occupation and Iraqis continue to die in great numbers"
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Major-General Rick Lynch, who also monitors military activities in the provinces of Babel, Karbala, Najaf and Wasit, said on Sunday the fighters were losing local support as thousands of former anti-American militias had now allied themselves with the US military.
Lynch also said that the quantity of Iranian bomb-making components being found in Iraq is increasing despite a fall in attacks and 20 Iranian-trained agents are still operating south of Baghdad.
He said: "Iranian influence is dominant at many levels."
Lynch's command is said to cover some of Iraq's most dangerous areas, including the so-called Triangle of Death, south of Baghdad.
Lynch said around 26,000 Iraqis were now working with the military to help secure the region.
He said: "Al-Qaeda has lost support. It does not have support from the local population."
A large number of the "concerned local citizens" - a term used by the US military - were former fighters who battled US-led forces after the fall of Saddam Hussein's government.
Lynch said nearly 16,000 of the 26,000 "concerned citizens" were being employed by the US military to guard checkpoints, bridges and other infrastructure and act as neighbourhood watchdogs.
In related news, British officers have met Iraqi fighters as part of efforts to end sectarian violence, an army officer said in an interview published on Sunday.
Major-General Paul Newton, a senior British army commander in Iraq, told The Sunday Telegraph that he leads a unit - along with a senior US state department official - that is contacting anti-government fighters and their sympathisers to try to find common ground.
For his part, Nuri al-Maliki, the Iraqi prime minister, said on Sunday that "terrorist acts" including car bombings and other al-Qaeda-style attacks have dropped by 77 per cent.
He called it a sign that Sunni-Shia violence was nearly gone from Baghdad.
"We are all realising now that what Baghdad was seeing every day - dead bodies in the streets and morgues - is ebbing remarkably," al-Maliki said.
Nevertheless, a trickle of violence continued on Sunday, with at least 10 people killed or found dead around the country.
The toll included a 12-year-old girl in Baghdad's Baladiyat area, who was killed by a roadside bomb that aimed for a US convoy but missed its target, police said.
On a different issue, though, al-Maliki criticised the US military, accusing it of thwarting attempts to execute former members of Saddam Hussein's government.
A court in September upheld the death sentences against Ali Hassan al-Majid, Saddam's cousin; Sultan Hashem, a former defence minister; and Hussein Rashid Muhammad, a former army commander.
Under Iraq's constitution the sentence should have been carried out within 30 days.
The three were convicted of genocide for their roles in a campaign against Iraq's Kurds in 1988.
Al-Maliki said the US embassy had played an "unfortunate role" in preventing the handover of the three prisoners.
The three, like many other high-ranking members of Saddam's government, are in US military custody.