Iraqi Prime Minister Nouri al-Maliki is facing tough questions from lawmakers about security lapses in the capital, two days after an attack killed 127 people and wounded 400 in Baghdad.
Parliament convened a special session Thursday to find out how bombers have been able to stage three massive attacks in the capital since August.
Lawmakers who came out of the closed-door session told reporters that Mr. Maliki said political and sectarian disputes are to blame, and he said security services need to be de-politicized. Reporters are not present at the session, so the comments could not be independently confirmed.
An al-Qaida-linked group known as the Islamic State of Iraq has claimed responsibility for Tuesday's bombings and warned of more attacks.
Meanwhile, U.S. Defense Secretary Robert Gates is in Iraq on a previously unannounced visit.
A Pentagon spokesman says Gates is expected to meet with Iraqi President Jalal Talabani and Mr. Maliki, as well as senior U.S. military commanders.
Gates arrived in Baghdad Thursday after a visit to Afghanistan.
Both the Iraqi government and the U.S. military have warned of a rise in violence in the run-up to Iraq's general elections, set for Sunday, March 7.
The United States has tied troop withdrawal to those elections.
U.S. defense officials Thursday said plans to draw down U.S. troops remain on track. Under a U.S.-Iraq security agreement, all U.S. forces must withdraw from Iraqi territory by the end of 2011.
Some information for this report was provided by AFP, AP and Reuters.