BAGHDAD — The U.S. military distanced itself Sunday from remarks declaring al-Qaida in Iraq close to defeat, saying the terror network is "off-balance and on the run" but remains a very lethal threat.

However, Rear Adm. Patrick Driscoll, a military spokesman, said violence has dropped some 70 percent since a U.S. troop buildup began nearly a year ago.

Underscoring the continuing dangers, a roadside bomb targeted a patrol of U.S.-allied Sunni Arab fighters near a mosque in northern Baghdad Sunday, killing one of the so-called Awakening Council members and wounding three others, a police official said.

Driscoll was responding to a question about comments made Saturday by U.S. Ambassador Ryan Crocker, who said Iraqi forces have made important progress in confronting extremists.

"You are not going to hear me say that al-Qaida is defeated, but they've never been closer to defeat than they are now," Crocker said, speaking in Arabic to reporters during a visit to the Shiite holy city of Najaf.

Driscoll said the number of attacks in the past week had "decreased to the level not seen since March 2004," due to recent military operations against Shiite militias in Baghdad's Sadr City and the southern city of Basra, as well as Sunni insurgents in the northern city of Mosul.

But he warned al-Qaida in Iraq maintains the ability to stage suicide bombings and other deadly attacks.

"They certainly are off-balance and on the run," Driscoll said during a news conference in the U.S.-protected Green Zone in Baghdad. But, he added, the group "remains a very lethal threat."

The U.S. military has been cautious in touting recent security gains amid fears that al-Qaida and other insurgents are trying to regroup after suffering setbacks from military operations as well as a Sunni revolt against the terror network.

Sunni tribal leaders who have joined forces with the Americans have frequently been targeted by suspected insurgents trying to derail the movement that has been credited as a key reason for the sharp decline in violence over the past year.

The other factors include a troop buildup of some 30,000 additional American forces, which is currently being reduced, and a fragile cease-fire order by anti-U.S. Shiite cleric Muqtada al-Sadr.

In the past two months, Iraqi forces have launched three major operations: cracking down on Shiite militiamen in Basra and on al-Qaida in Iraq militants in the northern city of Mosul, and deploying in the Baghdad Shiite militia stronghold of Sadr City.

Thousands of Iraqi forces moved into Sadr City last week, imposing control for the first time in years, and the deployment has occurred with little violence so far.

But over the past several days violence has broken out in other Shiite districts of Baghdad as Iraqi forces move against militias there, including the powerful Mahdi Army loyal to anti-U.S. cleric Muqtada al-Sadr.

Clashes broke out before midnight Saturday between Shiite gunmen and U.S.-Iraqi troops in the Amin area in eastern Baghdad, killing two civilians and wounding three others, including a 4-year-old boy, according to police and hospital officials.

The officials all spoke on condition of anonymity because they weren't authorized to release the information. The U.S. military said American troops targeted Shiite gunmen after observing them moving weapons into vehicles late Saturday in the area, wounding one of the militants.

Al-Sadr's supporters accused Prime Minister Nouri al-Maliki on Saturday of seeking to eliminate their movement and warned that "dark clouds" hang over a truce that has so far held in Sadr City.

Iraqi Defense Ministry spokesman Maj. Gen. Mohammed al-Askari, meanwhile, said security forces had released 251 detainees captured during operations in Mosul and surrounding areas, but 1,030 remained in custody.

He said some 2,000 al-Qaida and other Sunni insurgent fighters were believed to have been in the city before the sweep was launched. He said most of the militants who managed to flee the offensive in Ninevah province, of which Mosul is the capital, were being pursued in other provinces.

"Now they are in a confused situation," he said at a joint news conference with Driscoll. "We will not allow them to reorganize themselves."