Gen. David Petraeus, the top US commander in Iraq, has pushed for a so-called "pause" in further redeployment of US troops.
Critics have called for a quicker withdrawal of American soldiers, but commanders on the ground insist the slowdown is needed so a sharp increase in violence is not seen when US forces leave.
Separately, the US military said in a statement Tuesday that a brothel in northern Iraq was attacked the day before. The Americans blamed the attack on al-Qaida insurgents, but local police did not speculate on who carried out the killings.
Iraqi police said the attack in Mosul killed three prostitutes and wounded two others.
There have been a string of attacks against women deemed immoral in recent months, including the bombing of hair styling salons and the frequent murder of women not wearing traditional clothing in the southern city of Basra.
Meanwhile, at least four civilians were killed overnight in the Baghdad Shiite neighborhood of Sadr City, hospital officials said Tuesday. Some 21 people were wounded at the same time in Sadr City, which has seen fierce fighting between the Mahdi Army militia and US and Iraqi troops.
Clashes in the sprawling slum of 2.5 million people that serves as a power base for radical Shiite cleric Muqtada al-Sadr and his Mahdi fighters have raged for five weeks, since the Iraqi government began a crackdown on the militants in southern Iraq.
Hassan al-Rubaie, a Sadrist lawmaker, suspended his seat in parliament on Tuesday to protest the fighting in Sadr City. He said he held the government of Prime Minister Nouri al-Maliki responsible for the fighting in the slum.
The lawmaker also blamed Iran for interfering with Iraq's security and said the neighboring nation was causing much of the violence by supplying money, weapons and training to Iraqi fighters, a charge US commanders have repeatedly made. Iran denies the allegations.
Meanwhile, US and Iraqi forces raided two police stations and arrested 48 policemen suspected of having links to Shiite militias late Monday in the Baghdad neighborhood of Shula, a Shiite stronghold, a policeman said on condition of anonymity as he was not authorized to speak to the media.
Elsewhere, two policemen were killed Monday night in clashes with unidentified gunmen in Mosul, a provincial policeman said on condition of anonymity as he was not authorized to speak to the media. Around the same time in eastern Mosul, two gunmen were killed by police.