The inspector general at the Department of Justice issued a report Monday criticizing the treatment of aliens held on immigration charges in connection with the investigation of the Sept. 11, 2001, terrorist attacks.

The report, almost 200 pages long, describes bureaucratic delays by the FBI and former Immigration and Naturalization Service that Inspector General Glenn A. Fine (search) said resulted in unnecessarily harsh treatment for detainees.

"The FBI should have expended more effort attempting to distinguish between aliens who it actually suspected of having a connection to terrorism from those aliens who, while possibly guilty of violating federal immigration law, had no connection to terrorism but simply were encountered in connection with a [FBI terrorism investigation] lead," Fine wrote in his findings.

The inspector general found that the INS held some of the 762 people detained in the 11 months after the attack for more than a month without telling them what they had been charged with.

Fine wrote it "affected the detainees' ability to understand why they were being held, obtain legal counsel, and request a bond hearing."

Fine also noted that oftentimes FBI agents were so busy with other work that they delayed getting out notices that would allow the detainees to be released. He added that confinement conditions at the primary holding centers in Brooklyn, N.Y., and Paterson, N.J., were below par.

However, the report notes that the Justice Department "faced enormous challenges as a result of the Sept. 11 terrorist attacks, and its employees worked with dedication to meet these challenges. The findings of our review should in no way diminish their work."

Justice Department spokeswoman Barbara Comstock said none of the actions taken by the department were outside the law and they "make no apologies" for using the tactics they did.

"Our policy is to use all legal tools available to protect innocent Americans from terrorist attacks. We make no apologies for finding every legal way possible to protect the American public from further terrorist attacks," Comstock said.

Justice Department officials said that all of those detained were charged with immigration violations, although some later had criminal charges added, including charges of overstaying visas, eluding previous deportation orders, entering the country illegally or entering with invalid immigration documents.

Officials also said "solid indications" reveal a link between a small number of those detained and terrorist organizations, although none was ever formally charged with terrorism.

In responding to criticism as to how long it took the FBI to check the backgrounds of detainees, one law enforcement official said: "These aren't one-hour crime TV shows. These are serious investigations.''

Justice officials defended the prolonged holding of immigration violators by pointing out that in February, the inspector general reported that high-risk aliens released on their own recognizance after being detained for visa violations frequently flee in order to avoid deportation.

The IG report found that of those located and deported by the INS, only 6 percent came from countries that are state sponsors of terrorism. Thirty-five percent of those removed had criminal records as well as immigration violations.

Fox News' Anna Stolley contributed to this report.