The suicide bombers who killed 95 people in devastating attacks at Iraqi government ministries on August 19 were recently released from U.S. custody, a senior interior ministry official said on Sunday.
The truck bombings in Baghdad also wounded 600 people in what was the worst day of violence to hit the country for 18 months, dealing a major blow to the nation's security efforts in the wake of a major pullout of U.S. troops.
"The suicide bomber who blew himself up at the ministry of foreign affairs was released three months ago from Camp Bucca," the official told AFP on condition of anonymity, referring to the U.S. jail near Basra.
"The suicide bomber who blew himself up outside the ministry of finance was also released a few months ago from the same jail."
Since the start of this year 5,236 prisoners have been released from U.S. custody and 1,179 detainees handed over to the government of Iraq, according to figures released on Sunday.
Less than 9,000 prisoners are still in American-run prisons.
"We have no proof that a former detainee was involved in the bombings," a U.S. army spokesman told AFP.
"The government of Iraq is still investigating the attacks, and it would be inappropriate for us to speculate as to who may have been involved while the investigation is ongoing."
The interior ministry official, however, told AFP that 14 suspects had been arrested in the wake of the attacks and that the truck bombs were prepared in southern Baghdad.
"The vast majority of them were released in recent months from Camp Bucca," he said, noting that all of the suspects were from Nineveh and Salaheddin provinces.
"Each of them had a precise role. One was responsible for buying the trucks. One was in charge of making sure they could enter Baghdad. One made sure that the explosives were packed on the trucks and others were the suicide bombers."
The official said interrogations of the suspects had uncovered that a third truck found in Baghdad on the same day as the other attacks did not explode because it broke down before reaching its target.
"Until now, we cannot establish if the suspects have any links with foreign countries," the official added.
The disclosures contradict an official version of events which last Sunday saw the government parade a former police chief who they said orchestrated the finance ministry bombing.
Wissam Ali Kadhem Ibrahim admitted on video to plotting that attack.
"I received a call a month ago from my boss in the (Baath) party Sattam Farhan in Syria to do an operation to destabilise the regime," Ibrahim said, alluding to executed dictator Saddam Hussein's now outlawed political movement.
The 57-year-old suspect said the truck bomb was prepared in Khalis, northeast of Baghdad, and that he had called a contact in the nearby town of Muqdadiyah to ensure its safe passage to the capital.
Ibrahim, who said he was a chief of police in Diyala until 1995 under Saddam's rule, said he had worked as a lawyer until 2002 but then became a leading Baathist official in the restive province northeast of Baghdad.
Major-General Qassim Atta, Baghdad spokesman for the Iraqi army, told reporters that Ibrahim was the main person responsible for the attack at the ministry of finance.
The second truck bombing occurred just minutes later at the foreign ministry.
Relations between Iraq and Syria deteriorated markedly after the video footage of Ibrahim was released, leading to a respective recalling of ambassadors.
The government aired a second video confession on Sunday, which featured a man named Mohammed Al-Shamari, 29, they said was from Saudi Arabia and allegedly a high-ranking Al-Qaeda operative in Diyala.
The footage showed Shamari saying he received training at a military camp in northern Syria and that the Syrian secret service helped him to enter Iraq.
Meanwhile a civilian was killed and eight other people were wounded in two separate attacks in Baghdad on Sunday, an interior ministry official said.
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