The prisoners, who were serving a variety of sentences from five years in jail to death for crimes ranging from drug offences to murder, had not yet been recaptured but an inquiry has been launched, he said.

"Eleven prisoners have escaped from prison," said Sagvan Jameel, head of the Zirga jail in the northern Kurdish province of Dohuk, in a press release.

"They dug a tunnel 80 metres long and escaped through it."

"The prisoners did not leave any traces of how they dug the tunnel," he later told AFP. "We are surprised."

Zirga prison, opened in 2008, houses around 600 inmates and is run by the Iraqi autonomous region of Kurdistan's ministry of labour and social affairs.

Iraq's Kurdish region in the north, comprised of three provinces including Dohuk, administers most of its own affairs, including its penal system.

Iraq bombs kill two Shiite pilgrims, two police
Baghdad (AFP) Jan 7, 2012 - Bomb attacks against police and Shiite pilgrims in central Iraq on Saturday killed four people, two officers and two worshippers, and wounded 10 others, officials said.

In the former insurgent bastion of Fallujah, 60 kilometres (40 miles) west of Baghdad, a roadside bomb against a group of federal policemen killed two of them and wounded one other, according to federal police Captain Ali Abdulsaheb.

The attack occurred at around 7:00 pm (1600 GMT) near the Abdulaziz al-Samarraie mosque in the centre of Fallujah, part of Sunni Anbar province.

Two separate attacks against Shiite pilgrims ahead of Arbaeen commemorations later this month, meanwhile, killed two and wounded nine others, security and medical officials said.

In Mahmudiyah, which lies in a confessionally-mixed area south of Baghdad known as the Triangle of Death for the high levels of violence there in 2006 and 2007, a roadside bomb against a group of pilgrims killed one and wounded five others, officials from the ministries of interior and defence said.

And in the restive city of Baquba, capital of Diyala province north of Baghdad, a magnetic "sticky bomb" attached to a car transporting pilgrims exploded, killing one and wounding four, according to Firas al-Dulaimi, a doctor at the city's hospital, and a security official.

Arbaeen marks 40 days after the Ashura anniversary commemorating the killing of Imam Hussein, one of Shiite Islam's most revered figures, by the armies of the Caliph Yazid in 680 AD.

Attacks against Shiites in Baghdad and north Iraq on Thursday left 70 people killed and more than 100 wounded, the country's highest death toll since August, amid a political row between Shiite-led authorities and Iraq's main Sunni-backed bloc, stoking sectarian tensions.

Staff Sergeant Frank Wuterich pleaded not guilty Thursday at Camp Pendleton, California, where the first day of proceedings was spent questioning potential members of the panel which will decide his fate.

The 31-year-old faces nine counts of voluntary manslaughter and other charges for his role in 24 deaths, many of them women and children, in the Iraqi town of Haditha on November 19, 2005.

The jury, which was finalized Friday, is composed of eight members: four officers and four enlisted personnel, ranking from gunnery sergeant to lieutenant colonel.

Wuterich formally entered "not guilty" pleas to all charges, including counts of dereliction of duty and assault. If convicted of all the offenses at the month-long trial, he could be sentenced to more than 150 years in prison.

But his lead lawyer said he was confident the Iraq veteran would be exonerated.

"We're confident that the truth about Haditha will come out during the trial and that Staff Sergeant Wuterich will be acquitted of all charges," Neal Puckett told AFP Thursday at the military base north of San Diego.

Wuterich, who had no previous combat experience, was the squad leader who sent his men into a village to hunt for insurgents following a roadside bombing that killed a fellow Marine and injured two other US troops.

Nineteen people were killed inside houses, along with five men who pulled up near the scene in a car, triggering one of the most controversial criminal cases involving the US military during the nearly nine-year-long Iraq war.

The Marines said after the violence in Haditha that 15 Iraqis had been killed by the roadside bomb that killed the American soldier.

But a subsequent investigation by Time magazine showed most of the dead were killed as Marines swept through three houses near the site of the bombing.

Lawyers for the Marines said insurgents hid behind civilian homes and opened fire, sparking a shootout that would fall within legal rules of engagement.

Military prosecutors said however there were no such insurgents and that the Marines initiated a bloody three-hour rampage to avenge the death of their comrade.

The victims included 10 women or children killed at point-blank range.

The other seven Marines charged in the case have been exonerated through various legal rulings, fueling anger in Iraq, where authorities had pushed for US troops to be subject to Iraqi justice before the US pullout in December.

But Wuterich's attorneys have exhausted all possible appeals on behalf of their client, including an attempt to dismiss charges based on the forced retirement of one of the military defense attorneys.

Another ruling against the defense team allowed military prosecutors access to unaired portions of the CBS "60 Minutes" interview of Wuterich, which was conducted prior to charges being filed.

Wuterich remains on active duty at Camp Pendleton while awaiting resolution of his case.