Iraqi Interior Minister Jawad al-Bolani is to appear before furious MPs on Thursday after Prime Minister Nuri al-Maliki sacked Baghdad's security chief over attacks in the capital that killed 127 people.
Maliki acted shortly after police claimed that the bombers, who also wounded around 450 people, were backed by groups in Syria or Saudi Arabia.
But later an Al-Qaeda group, the Islamic State of Iraq (ISI), issued a statement on a forum for Muslim extremists saying it carried out the bombings, according to US monitoring group SITE.
The statement, translated by SITE on Wednesday, threatened more attacks, saying the latest carnage was the "third wave" in an ISI campaign following bloody days on August 19 and October 25 that left over 100 people dead.
"The list of targets will not end, with permission from Allah, until the flag of monotheism is raised once against on the land of Baghdad and the sharia of Allah rules the land and the worshippers," it said.
The group also claimed responsibility for a suicide bombing in Tikrit, the hometown of executed Iraqi dictator Saddam Hussein, that killed a senior anti-terror officer on December 3.
Lawmakers have demanded answers over Tuesday's blasts, which have killed more people than in all of November, undermining government claims of improved security ahead of March 7 elections.
Although they have called for Maliki and ministers with security portfolios to appear, only Bolani, whose ministry is responsible for police, has confirmed that he will submit to questioning.
"I am ready to go to parliament on the condition that the session be public," he told AFP earlier.
Meanwhile, Maliki fired the military officer in charge of the capital's security.
"Nuri al-Maliki, as the commander in chief of the armed forces, ordered the removal of Lieutenant General Abbud Qanbar from his post," a statement from the premier's office said late on Wednesday.
Lieutenant General Ahmed Hashem Awudeh will succeed Qanbar, who will be moved to Awudeh's old job as deputy army chief of staff.
Earlier, a senior policeman said the explosives used in the attacks were manufactured abroad and that the bombers were backed by groups in Syria or Saudi Arabia.
"This material could not have been manufactured in Baghdad; it came from abroad," Major General Jihad al-Jaabiri, the explosives unit chief told reporters.
"Neighbouring countries helped them. The operation required lots of funding, which came from Syria or Saudi Arabia."
Jaabari said Al-Qaeda and backers of the Baath party of executed dictator Saddam Hussein were behind the blasts.
Tuesday's bombs all exploded within minutes of each other.
One suicide attacker detonated his payload at a finance ministry office, another struck at a tunnel leading to the labour ministry and a third drove a four-wheel-drive car into a courthouse.
A fourth bomber in a car struck a police patrol in Dora in south Baghdad, while a car bomb hit interior ministry offices in the centre of the capital.
Maliki, who has been sharply criticised by politicians since the bombings, called on television on Wednesday for unity among Iraqi leaders.
"I call (on all politicians) ... to avoid using these disasters to create conflicts during the election campaign because if the temple falls, it falls on everyone, and no one will be spared," he said.
In August and October, Baghdad was hit by bloody coordinated vehicle bombings against government buildings, puncturing confidence in the security forces.
Violence continued to hit the capital on Wednesday -- a roadside bomb in the predominantly Sunni north Baghdad district of Adhamiyah killed two people and wounded seven, an interior ministry official said.
Also in Adhamiyah, a sniper killed a policeman and a bomb hidden inside a mini-bus exploded, killing two people and wounding 11.
In Mahmudiyah, an ethnically mixed town just south of Baghdad, another bomb concealed inside a mini-bus killed three people and injured eight.
Attacks across Iraq dropped dramatically last month, with the fewest number of deaths in attacks recorded since the 2003 invasion. Official figures showed a total of 122 people were killed in November.
Both the Baghdad government and the US military have warned of a rise in attacks in the run-up to the election.
Despite Tuesday's attacks, US forces remain on track to begin withdrawing from Iraq in large numbers next year, said Admiral Michael Mullen, the chairman of the Joint Chiefs of Staff.
Copyright 2009 AFP Global Edition
