But the tip was too vague and came too late to stop the bombings, Defense Minister Abdul-Qader al-Obeidi told lawmakers, according to the legislator, who attended the discussion.
The special session of parliament was called to question Iraq's senior security chiefs, including the defense and interior ministers, about security gaps that allowed the third attack since summer against government sites in the capital.
"The ministers said that they cannot guarantee that such operations will not be repeated," Shiite legislator Haider al-Ibadi told reporters after the session ended.
Al-Ibadi said officials from the Interior Ministry and Baghdad security obtained information about a possible bomb plot on Tuesday. "And this information was spread to the security forces, but this tip lacked details and there was little time for the security forces to stop them," he said.
None of the security officials - who also included the national security minister and the Iraqi intelligence chief - spoke publicly after the session.
Later, Al-Iraqiya state television carried clips of al-Obeidi and Interior Minister Jawad al-Bolani addressing parliament. Those excerpts, however, did not include any comments about a tip-off before the attack.
In the televised excerpts, al-Bolani defended Iraqi security forces and said authorities thwarted attackers from hitting one of the targeted sites, the Labor Ministry. Al-Bolani also praised Iraqi police for confronting an attacker in another area of Baghdad.
"I think that the security forces have carried out their duties and the proof is that the terrorists were not able to reach their planned targets" in some cases, al-Bolani said in one excerpt broadcast on Al-Iraqiya.
Parliament wasn't satisfied.
Lawmakers took the ministers to task, demanding an adequate explanation for how suicide bombers slipped through security in heavily guarded downtown Baghdad to launch five bombs, all within an hour of each other.
Al-Ibadi said the security chiefs responded by pointing out that authorities opened fire on three of the suicide bombers, who still managed to detonate the cars they were driving. A fourth car bomb went unnoticed before it detonated.
In one of the clips shown on the Al-Iraqiya channel, al-Obeidi said security forces faced an enormous challenge because car bombs are increasingly being manufactured in Baghdad workshops and prepared near the target sites. He also attempted to shift some blame to parliament, complaining that military and intelligence officials have no money to recruit informants.
An official statement detailing the meeting and posted on parliament's Web site said al-Bolani blamed the security gaps on misunderstandings, bureaucracy and turf battles within the government. The statement also said Iraq's acting intelligence chief cited a lack of cooperation among government ministries.
Al-Ibadi signaled lawmakers might be open to spending up to $25 million to "help security forces gathering information."
The attacksthat set guidelines for a March 7 national vote. Prime Minister Nouri al-Maliki has been under intense pressure to assure a safe election.
Al-Maliki made his security aides answer to parliament after they previously refused to attend similar sessions following bombings on Aug. 19 and Oct. 25. More than 250 were killed in those attacks. Al Qaeda has claimed responsibility for the three attacks.
While violence overall has declined dramatically in Iraq, insurgents have targeted Iraqi security forces and civilians.
On Saturday, a roadside bomb targeting a patrol killed three policemen in northern Iraq, said police Col. Sherzad Morferi. The bomb wounded two more in the attack in the oil-rich city of Kirkuk, he said.
Americans continue to be targeted, too. A roadside bomb hit a U.S. vehicle in northwest Baghdad on Saturday, injuring three American soldiers, said military spokesman Master Sgt. Nicholas Conner. He had no additional details.