WASHINGTON — Attorney General Alberto Gonzales yesterday blamed delays in trying detainees at Guantanamo Bay on legal challenges filed by their lawyers. Those trials may start by this summer, Mr. Gonzales told Associated Press reporters and editors. He said rules for the military commission are being sent up to Capitol Hill this week.

“It’s not for lack of trying,” Mr. Gonzales said, when asked about the legal fate of detainees who have been held at the military facility, in some cases for five years. “We are challenged every step of the way.”

“We are trying as hard as we can to bring these individuals to justice,” he said.

In the wide-ranging interview that lasted an hour, the attorney general defended a number of Bush administration policies criticized by Democrats and civil libertarians as overstepping legal boundaries, including intelligence gathering and the recent firing of U.S. attorneys.

Mr. Gonzales bristled at the suggestion by Democratic senators that the Justice Department’s request for the resignations of several U.S. attorneys was politically motivated or was intended to circumvent the Senate confirmation process.

On another issue, Mr. Gonzales said Congress allows the Pentagon to examine banking records of Americans suspected of terrorism or espionage. The little-known power has been on the books for decades and was recently reauthorized in the Patriot Act, but some lawmakers are questioning whether it is an improper expansion of the Defense Department’s domestic role.

“If Congress gives them the authority, I think they probably ought to be exercising that authority in connection with national security investigations,” Mr. Gonzales said.

The Bush administration has been widely criticized for its detention of about 395 men at Guantanamo, some without being officially charged, on suspicion of links to Al Qaeda or the Taliban. The government has characterized the detainees as enemy combatants who should have fewer legal protections than civilians in America’s courts.

Military officials say between 60 and 80 detainees will be charged and brought to trial. Another 85 men have been cleared for release or transfer to other countries.

Defense lawyers have challenged the validity of the new law, which President Bush signed October 17, and have raised the possibility that the military trials will be struck down by a federal appeals court or the Supreme Court.

Michael Ratner, president of the Center for Constitutional Rights, called Mr. Gonzales’s remarks yesterday “a convoluted view of the world.”

“We’ve been trying for five years to get the majority of the detainees in federal court,” Mr. Ratner said. “They’ve resisted from the first day, when they took people to Guantanamo.”

On another topic, Mr. Gonzales said the Justice Department was indicting 148 illegal immigrants who acquired other people’s Social Security numbers and other personal information to get jobs at Swift & Co. meat-packing plants.

The indictments, in six states, follow federal raids on the plants last month in the largest-ever workplace crackdown on illegal immigration. The raids led to the arrests of nearly 1,300 employees and temporarily halted operations at the Greeley, Colo.-based meat processor.

In response, 18 former Swift employees sued the company for $23 million, charging it conspired to keep wages down by hiring illegal immigrants.

“Obviously, we’re concerned about identity theft in this country,” Mr. Gonzales said. He said the Bush administration is studying ways to curb identity theft, including better ways for police to report the crime, and to reduce the access that thieves have to Social Security numbers.

The federal indictments include: 53 in Texas, 30 in Iowa, 26 in Nebraska, 20 in Minnesota, 18 in Utah and one in Colorado. Additionally, local prosecutors are bringing state charges against the immigrants, including 80 in Cache County, Utah, and 18 in Weld County, Colo.