Anti-U.S. cleric Muqtada al-Sadr may let a six-month cease-fire expire as soon as Saturday, a move that could send his Shiite militia fighters back to the streets and jeopardize security gains that have led to a sharp decline in violence.

Iraqi police, meanwhile, held funerals Wednesday for 14 officers killed the night before as they responded to a rocket attack launched from a predominantly Shiite neighborhood against U.S. bases in the capital.

A U.S. military spokesman also said a U.S. civilian was killed and a number of U.S. troops and civilian personnel were wounded in a previously unreported rocket attack in the southeastern area of Rustamiyah on Tuesday night.

Rear Adm. Gregory Smith, a U.S. military spokesman, did not elaborate, but there is a U.S. base in the predominantly Shiite area.

In a separate attack, three American troops were killed by a roadside bomb Tuesday night in northwestern Baghdad, the U.S. military said.

Al-Sadr's Shiite Mahdi Army is among the most powerful militias in Iraq, and the cease-fire he ordered last August has been credited with helping reduce violence around Iraq by 60 percent or more in the past six months.

Sheik Salah al-Obeidi, a spokesman for al-Sadr in the Shiite holy city of Najaf, said that if the cleric failed to issue a statement by Saturday saying the cease-fire was extended, "then that means the freeze is over." Al-Sadr's followers would be free to resume attacks.

On an Internet site representing al-Sadr, al-Obeidi said that al-Sadr "either will announce the extension or will stay silent and not announce anything. If stays silent, that means that the freeze is over."

Al-Obeidi said that message "has been conveyed to all Mahdi Army members nationwide."

Smith, the U.S. military spokesman, said in an e-mailed statement that the cease-fire declared by al-Sadr's last August was good for the Iraqi people.

"Al-Sayyid Muqtada al-Sadr's cease-fire has been helpful in reducing violence and has led to improved security in Iraq. We would welcome the extension of the cease-fire as a positive step," he said, using an honorific reserved for descendants of the Prophet Muhammad.

While the U.S. has welcomed the cease-fire, it also has insisted on continuing to stage raids against what it calls Iranian-backed breakaway factions of the Mahdi Army militia — moves that have angered the cleric's followers.

Influential members of al-Sadr's movement said earlier this month they had urged the radical cleric to call off the cease-fire, which initially was set to expire at the end of the month.

Al-Sadr's followers have claimed the U.S.-Iraqi raids, particularly in the southern Shiite cities of Diwaniyah, Basra and Karbala, are a pretext to crack down on the wider movement, which has pulled its support for the Washington-backed government.

A Sunni parliament member, Asmaa al-Dulaimi, said if the truce were broken it would hurt the prospects for national reconciliation and "further deteriorate the security situation nationwide."

"Resuming their activities, whether against the government or civilians, will lead to a new confrontation with them," she said.

Smith, at a news conference Wednesday, blamed Iranian-backed Shiite militias for a series of deadly rocket attacks in Baghdad, the most intense to hit the capital in weeks amid a steep decline in violence since a U.S.-Iraq campaign against Sunni and Shiite extremists began a year ago Feb. 14.

Rockets slammed into U.S. outposts in Baghdad Tuesday night and Smith said three U.S. soldiers were wounded, instead of four as was previously announced.

Iraqi police responding to the attack found an abandoned truck loaded with rockets, but one of them exploded before it could be defused.

Brig. Gen. Jihad al-Jubouri, head of the anti-bombing squad at the Interior Ministry, said 11 bomb experts and three other officers were killed. Officials initially had said that as many as 15 police were slain and up to 27 wounded.

On Wednesday, a band played as four pick-up trucks carried the coffins of the slain Iraqi police in a slow-moving funeral procession. Interior Minister Jawad al-Bolani walked with other officials at the back of the line.

"Their selfless bravery no doubt saved the lives of countless innocent Iraqis had the special groups been able to successfully fire from the truck," said Smith, the U.S. military spokesman.

On Monday, 16 rockets slammed into an Iraqi housing complex near the Baghdad international airport and Camp Victory, the main U.S. military headquarters, killing at least five people and wounding 16, including two U.S. soldiers.

Six Iraqi suspects detained near the launching sites all had explosives residue on their bodies, Smith said, adding that troops also seized 19 launching systems, one 107 mm rocket ready to be fired and other high explosives and munitions.

Meanwhile, three Iraqi children were killed and seven others wounded when they were hit by an insurgent mortar attack while playing soccer outside a military supply area on Tuesday near Balad, Smith said.

And in Diyala province north of Baghdad, where U.S. and Iraqi forces are working to push out Al Qaeda in Iraq, a homicide bomber's belt detonated near a line of people who were buying bread Wednesday, killing seven and wounding 17, said an official in the provincial command operation center. The official spoke on condition of anonymity because he wasn't authorized to release the information.