WASHINGTON, Aug. 30 — An independent commission established by Congress to assess Iraq’s security forces will recommend remaking the 26,000-member national police force to purge it of corrupt officers and Shiite militants suspected of complicity in sectarian killings, administration and military officials said Thursday.

The commission, headed by Gen. James L. Jones, the former top United States commander in Europe, concludes that the rampant sectarianism that has existed since the formation of the police force requires that its current units “be scrapped” and reshaped into a smaller, more elite organization, according to one senior official familiar with the findings. The recommendation is that “we should start over,” the official said.

The report, which will be presented to Congress next week, is among a number of new Iraq assessments — including a national intelligence estimate and a Government Accountability Office report — that await lawmakers when they return from summer recess. But the Jones commission’s assessment is likely to receive particular attention as the work of a highly regarded team that was alone in focusing directly on the worthiness of Iraq’s army and police force.

Its harsh indictment of a key institution in Prime Minister Nuri Kamal al-Maliki’s government is likely to be seized on by Democrats in Congress and other critics of the Bush administration’s Iraq strategy as further evidence that a fundamental shift in American policy is required.

However, a new attempt to disband an Iraqi force would also be risky, given the armed backlash that followed the American decision to dissolve the Iraqi Army soon after the invasion of 2003.

Bush administration officials were briefed on the report this week, and they said on Thursday that they were studying its recommendations as part of a strategy review that will include testimony next month from Gen. David H. Petraeus and Ambassador Ryan C. Crocker.

Geoff Morrell, a spokesman for Defense Secretary Robert M. Gates, said that an American effort to retrain the Iraqi police forces was under way. Mr. Morrell said that Pentagon officials believed that such an effort could succeed in removing sectarianism from the ranks without requiring a complete overhaul of the Iraqi force.

“We’re not giving up on the Iraqi National Police,” Mr. Morrell said, adding that the United States and Mr. Maliki’s government were “both committed to seeing it through.”

According to several administration officials, the Jones commission also reached largely positive conclusions about the Iraqi Army’s performance since the start of the new security strategy in Iraq — a sign, several officials said, that a determined American effort to remake Iraqi institutions holds some promise of success.

The officials who agreed to discuss the commission recommendations did so in some cases because they believed that disclosing them publicly would help diffuse their impact and focus attention on the Petraeus-Crocker report. Members of the commission and their aides declined to speak about the report on Thursday.

The Jones commission, which has 14 members, including former or retired military officers, Defense Department officials and law enforcement officers, was created this year by Congress to study the Iraqi security forces and report its findings this fall. Members of the commission made three trips to Iraq and met with senior American commanders and Iraqi officials. National police units were designated earlier this year to play a major role securing neighborhoods after United States and Iraqi Army units cleared the areas of insurgents. But the police have proven to be a tenuous element of that strategy. Rampant sectarianism as well as supply and equipment problems have led to frequent complaints by the American military that the national police have been ineffective or openly allied with Shiite militants in many neighborhoods.

American commanders on the ground in Shiite-controlled areas of Baghdad say that the local police actively subvert efforts to loosen the grip of militias, and in some cases, attack Americans directly. One commander in northwest Baghdad said most bomb attacks against American patrols in the area this spring occurred close to police checkpoints.

Officers involved in training the national police units, which fall under the Shiite-dominated Interior Ministry, acknowledged deep problems with the police but said that they had been working methodically for months on retraining national police units to do exactly what the Jones commission was proposing — purge them of Shiite militants and install better leaders.

Officers in Iraq said that during the course of the training effort 9 police brigade commanders and 17 battalion commanders had been relieved of duty for various acts of misconduct, in particular illegal actions of a sectarian nature as well as corruption.