Sept. 10 (Bloomberg) -- General David Petraeus told the U.S. Congress today that security progress in Iraq should allow the number of American troops to be cut by mid-2008 to the level that preceded a buildup this year.

Petraeus has recommended that some of the units be pulled out starting this month, beginning with a Marine Expeditionary Unit, followed by the withdrawal of a brigade in mid-December and the departure without replacement of four more brigades and two Marine battalions by July.

Reducing the force can occur ``without jeopardizing the security gains that we have fought so hard to achieve,'' so long as progress continues as anticipated, Petraeus, the U.S. military commander in Iraq, told a joint hearing of the House Armed Services and Foreign Affairs committees.

The testimony of Petraeus, 54, and Ambassador Ryan Crocker, 58, has long been anticipated by lawmakers as a potentially pivotal moment in the debate over U.S. policy on Iraq. They will testify again tomorrow before two Senate committees.

The number of brigades in Iraq grew to 20 from 15 as part of the buildup, bringing the total force to 168,000 personnel from 130,000. Petraeus said it is premature to speculate on troop reductions after July 2008.

Traumatized Country

Crocker, a veteran of postings in Arab capitals, told lawmakers that Iraqis are making slow progress toward building a viable political system from a society traumatized by the brutal rule of Saddam Hussein. The dictator, who repressed the majority Shiite population and the Kurds of northern Iraq, was executed last year by the Iraqi government.

``A secure, stable, democratic Iraq at peace with its neighbors is, in my view, attainable,'' Crocker said. ``There will be no single moment at which we can claim victory. Any turning point will likely be recognized only in retrospect.''

Petraeus said the military objectives of the so-called surge this year ``are in large measure being met.'' Civilian deaths have declined, and ``Iraqi security forces have also continued to grow and to shoulder more of the load.'' Al-Qaeda terrorist elements are coming under pressure, the general said. The willingness of Sunni tribes in Anbar province to fight al-Qaeda is spreading elsewhere, Petraeus said, citing that as a significant development in the war.

Still, Petraeus noted that progress has been ``uneven'' throughout the country and the number of civilian deaths remains ``too high.''

Differing Assessments

Iraqi Prime Minister Nuri al-Maliki told the Iraqi parliament today that violence was down 75 percent in Baghdad and nearby Anbar province since the U.S. surge.

Petraeus's assessment that violence in Iraq has fallen since the U.S. buildup was questioned last week in a report by Congress's investigative arm, the Government Accountability Office, which found the average number of daily attacks against civilians had remained about the same during the past six months.

Six in 10 Iraqis say security has diminished since the U.S. buildup, according to a survey by ABC News, the British Broadcasting Corp. and Japanese broadcaster NHK.

Petraeus also said the flow of military assistance from Iran to Iraqi militias has increased even after two meetings between Crocker and his Iranian counterpart. Petraeus accused an arm of Iran's Revolutionary Guard Corps, the Quds force, of training a Shiite militia force to fight a proxy war in Iraq.

No `Great Strides'

House Democrats opened the hearing by stressing the failures in Iraq. ``No one can make the case that the Iraqi government has made great strides,'' said Representative Ike Skelton, the Missouri Democrat who chairs the House Armed Services Committee, citing reports that show Iraqi leaders have failed to achieve economic and security benchmarks for unity.

``The witnesses must tell us why we should continue sending our young men and women to fight and die if the Iraqis won't make the tough sacrifices leading to reconciliation,'' Skelton said in a statement opening the hearing.

Tom Lantos, who chairs the House Foreign Affairs Committee, dismissed Petraeus's proposed withdrawal as ``token'' and said U.S. troops must get out now.

Petraeus defended his recommendation, saying it was the best way to sustain the gains achieved without ``rushing to failure.'' The key is to hand over responsibility to Iraqi security forces ``as quickly as we possibly can,'' he said.

Petraeus disclosed excerpts of an Aug. 16 Defense Intelligence Agency assessment that concluded a rapid troop withdrawal runs the ``high risk of disintegration of the Iraqi Security Forces'' and al-Qaeda ``regaining lost ground and freedom of maneuver.''

Hunter Defends Effort

The ranking Republican on the Armed Services Committee, Representative Duncan Hunter of California, defended the U.S. military effort in Iraq, saying it has reduced violence in the Sunni-dominated Anbar province west of Baghdad.

Hunter said he was angered by attempts to attack the credibility of Petraeus before the hearing. He pointed to a full- page advertisement in today's New York Times that says the commander is likely to become ``General Betray Us.'' The political movement MoveOn.org, which sponsored the ad, accuses Petraeus of ``cooking the books for the White House.''

White House spokesman Tony Snow said today the administration had ``not shaped'' the assessments. ``This is independent testimony prepared by two career professionals,'' he told reporters. Petraeus told the hearing he had written his testimony and not shared it with his superiors before delivering the remarks today.

Hecklers Removed

At several points, hecklers interrupted the hearing with antiwar outbursts. Skelton ordered the removal of several individuals, including one person who chanted ``war criminals'' and another who screamed ``war monger.''

According to the Hill newspaper, those arrested included Cindy Sheehan, who attracted international attention in 2005 when she camped outside President George W. Bush's ranch in Crawford, Texas.

Four rows of photographers, standing and kneeling, shot pictures as Petraeus and Crocker took their seats in what may be the most famous hearing in the room since singer Frank Sinatra testified in July 1972, denying allegations of ties to organized crime.

To contact the reporter on this story: Janine Zacharia in Washington at jzacharia@bloomberg.netTony Capaccio in Washington at acapaccio@bloomberg.net

Last Updated: September 10, 2007 17:15 EDT