After a contentious closed-door vote, the Senate intelligence committee approved a long-awaited report Thursday concluding that harsh interrogation measures used by the CIA did not produce significant intelligence breakthroughs, officials said.

The 6,000-page document, which was not released to the public, was adopted by Democrats over the objections of most of the committee’s Republicans. The outcome reflects the level of partisan friction that continues to surround the CIA’s use of waterboarding and other severe interrogation techniques four years after they were banned.

The report is the most detailed independent examination to date of the agency’s efforts to “break” dozens of detainees through physical and psychological duress, a period of CIA history that has become a source of renewed controversy because of torture scenes in a forthcoming Hollywood film, “Zero Dark Thirty.”

Officials familiar with the report said it makes a detailed case that subjecting prisoners to ­“enhanced” interrogation techniques did not help the CIA find Osama bin Laden and often were counterproductive in the broader campaign against al-Qaeda.

The committee chairman, Sen. Dianne Feinstein ­(D-Calif.), declined to discuss specific findings but released a written statement describing decisions to allow the CIA to build a network of secret prisons and employ harsh interrogation measures as “terrible mistakes.”

“I also believe this report will settle the debate once and for all over whether our nation should ever employ coercive interrogation techniques,” Feinstein said.

That conclusion has been disputed by high-ranking officials from the George W. Bush administration, including former vice president Richard B. Cheney and former CIA director Michael V. Hayden. Both of them argued that the use of waterboarding, sleep deprivation and other measures provided critical clues that helped track down bin Laden, the al-Qaeda leader who was killed in a U.S. raid in Pakistan in May 2011.

Largely because of those political battle lines, Republicans on the Senate intelligence committee refused to participate in the panel’s three-year investigation of the CIA interrogation program, and most opposed Thursday’s decision.

Sen. Saxby Chambliss of Georgia, the committee’s ranking Republican, said in a statement that the report “contains a number of significant errors and omissions about the history and utility of CIA’s detention program.” He also noted that the review was done “without interviewing any of the people involved.”

The 9 to 6 vote indicates that at least one Republican backed the report, although committee officials declined to provide a breakdown.

Other GOP lawmakers voiced support for the report’s conclusions. Sen. John McCain (Ariz.), who was a prisoner of war in Vietnam, issued a statement saying that the committee’s work shows that “cruel” treatment of prisoners “is not only wrong in principle and a stain on our country’s conscience, but also an ineffective and unreliable means of gathering intelligence.”

It could be months, if not years, before the public gets even a partial glimpse of the report or its 20 findings and conclusions. Feinstein said the committee will turn the voluminous document over to the Obama administration and the CIA to provide a chance for them to comment.

When that is completed, the committee will need to vote again on whether to release even a portion of the report, a move likely to face opposition from the CIA, which has fought to keep details of the interrogation program classified.

Even if it were released, the report would probably have little impact beyond providing new ammunition for a largely dormant interrogation debate.

The agency abandoned its harshest interrogation methods years before President Obama was elected, and the Justice Department began backing away from memos it had issued that had served as the legal basis for the program.

Earlier this year, the Justice Department closed investigations of alleged abuses, eliminating the prospect that CIA operatives who had gone beyond the approved methods would face criminal charges.

Civil liberties groups praised the report.