Federal agents and prosecutors in Phoenix ignored risks to the public and were primarily responsible for the botched effort to infiltrate weapons-smuggling rings in the operation dubbed “Fast and Furious,” according to a report released Wednesday by the Justice Department’s inspector general.

The long-awaited report also criticized senior officials at the Justice Department and its Bureau of Alcohol, Tobacco, Firearms and Explosives in Washington for lax oversight of the attempt to block the flow of weapons to Mexico’s violent drug cartels. Many of the weapons later turned up at crime scenes in Mexico and the United States, including one where a U.S. Border Patrol agent was killed.

The inspector general’s report recommended that the Justice Department review the actions of 14 officials and consider whether disciplinary action is warranted. Among them are former acting deputy attorney general Gary Grindler, Assistant Attorney General Lanny Breuer, former acting ATF director Kenneth Melson, former ATF special agent in charge William Newell and Deputy Assistant Attorney General Jason Weinstein.

The inquiry “did not find persuasive evidence that any supervisor in Phoenix, at either the U.S. Attorney’s Office or ATF, raised serious questions or concerns about the risk to public safety posed by the continuing firearms purchases or by the delay in arresting individuals who were engaging in the trafficking,” Michael Horowitz, the Justice Department’s inspector general, wrote in the 471-page report. “This failure reflected a significant lack of oversight and urgency by both ATF and the U.S. Attorney’s Office.”

In describing the actions of officials in Washington, the report said that “Fast and Furious received little to no supervision by ATF Headquarters despite its connection to a dangerous narcotics cartel in Mexico, the serious risk it created to public safety in the United States and Mexico, and its potential impact on the country’s relationship with Mexico.”

While the report criticized officials in Washington, it said Attorney General Eric H. Holder Jr. had no advance knowledge of the tactics and risks involved in the operation until after it was stopped.

Holder issued a statement saying that the report’s conclusions were consistent with the Justice Department’s assessment that the strategy was flawed and that the agency’s leadership did not attempt to “cover up information or mislead Congress about it.”

He said that Melson, who had been transferred from the acting ATF director post to another position at Justice, has resigned. Weinstein, a deputy assistant attorney general under Breuer in the criminal division, also has resigned, Holder said.

A Justice official said Breuer has been “admonished” by Holder but will not be disciplined. The inspector general’s report said that Breuer did not authorize the investigative activities in Fast and Furious and that there is no evidence indicating he was aware in 2009 or 2010 that ATF agents were not interdicting firearms.

But the report criticized Breuer for not informing the deputy attorney general or the attorney general in April 2010 when he learned that the ATF had used similar tactics in another Arizona case called “Operation Wide Receiver.” Breuer has already publicly apologized for that inaction.

The Justice official also said that Holder will not be taking any further disciplinary actions against department employees, including Grindler, who is now his chief of staff.

Fast and Furious allowed weapons from the United States to pass into the hands of suspected firearms smugglers so that they could be tracked to the upper levels of Mexican drug cartels. But the ATF lost track of about 2,000 guns, including AK-47-style rifles, and the report said the agency seized only about 100 weapons. Two guns linked to a suspected trafficker were found at the scene of the fatal shooting of Border Patrol agent Brian Terry in December 2010.

The report was based on interviews with 130 witnesses and a review of 100,000 documents over the past 18 months, according to the inspector general.

In a historic move in late June, the House of Representatives voted to find Holder in contempt for refusing to turn over some internal communications about the operation and its aftermath. Rep. Darrell Issa (R-Calif.), chairman of the House Oversight and Government Reform Committee, who praised the inspector general’s report, has requested that Horowitz testify at a hearing Thursday morning.

The report’s conclusions were harsher than expected, although not surprising to officials who have followed the unfolding story of Fast and Furious. Last year, after Holder requested the inspector general’s investigation, the Justice Department forced Dennis Burke, the U.S. attorney in Phoenix, to resign. Several other officials were reassigned, including Melson; Emory Hurley, the lead prosecutor for the case in Phoenix; and Newell, the special agent in charge of the Phoenix ATF office.

Phoenix ATF agents testified that they watched as gun-trafficking suspects bought hundreds of weapons. Some agents said they were ordered to let the guns “walk” so the agency could trace them to a firearms-trafficking ring. Several of their supervisors said that they never allowed gun-walking but instead were told by the U.S. Attorney’s Office in Phoenix that they did not have enough evidence to seize the weapons at the time.

ATF Acting Director B. Todd Jones accepted responsibility Wednesday for the failed gun operation.

“It’s a sad day,” he said at a briefing with reporters. “The OIG report is rightfully critical. . . . We have taken corrective actions to ensure that something like this never happens again.”