The study, conducted by a 20-member panel led by retired Gen. James Jones, is one of several independent studies Congress directed in May. A copy of the 37-page report was obtained by The Associated Press.
Overall, Jones found that Iraqi military forces, particularly the Army, show "clear evidence of developing the baseline infrastructures that lead to the successful formation of a national defense capability." But Baghdad's police force and Ministry of Interior are plagued by "dysfunction."
"In any event, the ISF will be unable to fulfill their essential security responsibilities independently over the next 12-18 months," the report states.
Jones, a former commander of U.S. troops in Europe and Marine Corps Commandant, is scheduled to testify before Congress on Thursday. Defense Secretary Robert Gates and other officials have already been briefed on the study, officials said last week.
released Tuesday by the Government Accountability Office found that Iraq had not met 11 of 18 political and security goals - a blunt assessment that challenges President Bush's findings on the war as he prepares to announce plans for the U.S. military campaign..
Meanwhile, Mr. Bush on Wednesday, and got a boost when Australian Prime Minister John Howard said his country's forces would remain in Iraq for the foreseeable future.
"If I didn't think we could succeed, I wouldn't have our troops there," Mr. Bush said. He added that it was important "that we hang in there with the Iraqis and help them."
In other developments:
Sen. John Warner, R-Va., the No. 2 Republican on the Senate Armed Services Committee, called for the Jones study earlier this year. He said he wanted a detailed assessment on the capability of Iraq's military and police forces because their success is considered by the Bush administration as necessary before U.S. troops leave.
The report is upbeat about progress made by the Iraqi army and special forces, noting these units have become more proficient in counterinsurgency and counterterrorism operations.
"They are gaining size and strength, and will increasingly be capable of assuming greater responsibility for Iraq's security," the report states, adding that special forces in particular are "highly capable and extremely effective."
But the report is much more pessimistic about Iraq's police forces. It describes the Iraqi police as fragile, ill-equipped and infiltrated by militia forces. And it is led by the Ministry of Interior, which is "a ministry in name only" that is "widely regarded as being dysfunctional and sectarian, and suffers from ineffective leadership."
Among the recommendations made in the report are:
The panel was comprised of 20 retired senior military officers, chiefs of police, as well as John Hamre, who served as deputy of defense during the Clinton administration. The group says it traveled three times to Iraq for a total of 20 days, and met with more than 100 Iraqi officials, 100 current and former U.S. government officials and a dozen leading non-governmental experts.