The Department of Veterans Affairs announced Thursday that a review of every grave in the national cemetery system found 15 sets of remains buried in the wrong spots and nearly 800 other problems.

Most of those other issues were unmarked or mismarked graves.

The department’s announcement came shortly after its inspector general released a report critical of how the VA initially accounted for the final resting place of generations of veterans and their families. That report was prompted by the discovery of errors at a national cemetery in Texas in 2011.

The VA’s examination was marred by a lack of “an impartial and independent review procedure,” the audit found. VA officials also did not “provide sufficient time and resources,” and “cemetery directors were overwhelmed and felt pressure to complete the review by the target date.”

After the inspector general requested that the VA examine its cemeteries with better procedures, the VA looked at nine cemeteries and found 146 problems that had not been reported, including at Winchester National Cemetery in Virginia, the audit found.

In a statement, Steve L. Muro, the VA’s undersecretary for memorial affairs, apologized to affected families and said the department “strives to operate the best cemetery system in the world. That is why we self-initiated this review of our entire cemetery system.”

The 14-month review encompassed 3.2 million grave sites in 131 national cemeteries and other burial sites under the management of the VA’s National Cemetery Administration. It was the first time the administration had taken on such a task in the 150-year history of the national cemetery system, where veterans from the Revolutionary War to the wars in Iraq and Afghanistan are buried.

Although the error rate was low — less than 0.0003 percent — Muro said that “one error is one too many.”

Rep. Jeff Miller (R-Fla.), the chairman of the House Committee on Veterans’ Affairs, said in a statement that “while the review was a step in the right direction, we are disappointed that parts of the process were rushed, mismanaged and lacked independent analysis.”

The VA discovered burial problems in 2011, when workers were testing the accuracy of new maps at Fort Sam Houston National Cemetery in San Antonio and realized that 47 markers were one space over from where they were supposed to be.

Officials said the majority of the errors occurred in graves at least 40 years old and 80 errors occurred in graves from the Civil War era.

The problems were largely the result of sloppy work during a renovation procedure known as “raise and realign.” Headstones and markers were temporarily removed from the ground and cleaned while sod was repaired. But workers then reinserted the markers in the wrong places.

Raise-and-realign work is what caused 50 headstones to be offset at Riverside National Cemetery, the audit found, an error that resulted in two people being buried in the wrong places. To save space at sought-after national cemeteries, family members are typically buried in the same plot. If a headstone is incorrectly marked, a loved one could end up in the wrong place.

Officials have said they have since adopted procedures that should prevent that problem.

The burial errors at Riverside were not included in the initial review, the audit found. In addition to Riverside and Winchester, the audit also found other previously unreported problems, at Wood National Cemetery in Wisconsin and Philadelphia National Cemetery.

At Winchester, more than half of the 60 errors were headstones that had sunk below ground. The audit also found that the cemetery’s map had not been updated since 1956, even though 10 percent of its burials have occurred since then.

The audit said that cemetery officials “could not explain why the errors were not identified” in the initial review.

In all, 54 cemeteries and burial sites across the country have reported problems. The revelations of issues in the VA’s system followed word of serious problems at Arlington National Cemetery — unmarked and mismarked graves, urns that had been unearthed and dumped in a dirt pile — that officials went to great lengths to remedy.

The VA said it, too, will tighten procedures as a result of the findings. It said Thursday that it will continue to conduct audits of 17 cemeteries where problems were discovered.

It also has required contractors pulling up tombstones during raise-and-realign projects to leave the headstones at the grave sites.

In addition, it is working to ensure that cemetery maps are updated and accurate.

Muro said the department will use “the experience gained over the last year to create a new grave site accounting system.”

Ray Kelley, the legislative director of Veterans of Foreign Wars, praised the VA for the steps it has taken.

“I don’t think there was any intended wrongdoing,” he said. “I think they are trying to correct all the wrongs.”