Despite a failure to follow guidelines designed to prevent civilian casualties, no American troops or pilots are expected to face charges or further investigation in a May airstrike that killed dozens of Afghan civilians, officials said Monday.

Senior officials including Secretary of Defense Robert Gates and Lt. Gen. Stanley McChrystal — who has been nominated to take over the Afghan war effort — have been briefed on the findings of the May 4 incident in Farah province in eastern Afghanistan.

Pentagon spokesman Geoff Morrell said at a press briefing Monday that it will be up to Central Command to release the full report.

Morrell said "there were some problems with the tactics, techniques and procedures" involving the airstrikes, including "the way in which close air support was supposed to have been executed."

But, he said later in the briefing, "I got no sense from anything I heard today that charges are imminent or warranted in this case."

Civilian deaths have long been a problem for U.S. forces in Afghanistan. But the Farah incident reignited Afghan anger and led President Hamid Karzai to demand an end to U.S. airstrikes in the country. A preliminary American report from an investigation into the attack put the number of civilian casualties as high as 30. Afghanistan’s Independent Human Rights Commission concluded that 97 civilians died in the attack, including 65 children and 21 women, while earlier Afghan government estimates rose as high as 140 civilian casualties.

During his Senate confirmation hearing earlier this month, McChrystal said any victory in Afghanistan must include a reduction in civilian deaths.

"Although I expect stiff fighting ahead, the measure of effectiveness will not be enemy killed. It will be the number of Afghans shielded from violence," he said.

"This is a struggle for the support of the Afghan people. ... I cannot overstate my commitment to the importance of this concept."

But, Morrell said, "I did not get any sense that there would be follow-on beyond [the report] — beyond General McChrystal taking additional measures once he hits the ground to determine how we can do a better job with regards to civilian casualties."

Officials have said the Farah incident began when an Afghan unit responding to reports of beheadings was ambushed by Taliban fighters. The Afghans called in a Marine unit, and a "several-hour" battle ensued.

Morrell acknowledged a number of civilians were killed, but claimed that the report found "they were greatly outnumbered by the Taliban killed in this incident."

The report faults U.S. troops for violating guidelines on initial airstrike planning in populated areas and for dropping ordnance without proper confirmation of targets, officials said.

Aircraft including four Navy F-18 Hornets and an Air Force B-1, using 2,000-pound bombs, were used for several bombing runs.

According to a New York Times article earlier this month, an official familiar with the inquiry said that "in several instances where there was a legitimate threat, the choice of how to deal with that threat did not comply with the standing rules of engagement."

In another one of the strikes, the Times reported, aircraft struck a compound where militants were amassing for a possible counterattack, violating rules requiring an imminent threat before putting areas with many civilians at risk.

In late May, Col. Greg Julian, the top U.S. military spokesman in Afghanistan, told Stars and Stripes that officials were seeking to declassify weapon-sight video and other intelligence that would show blame lies with the Taliban.

Morrell said the video was included in the briefing for Gates and McChrystal, but could not say whether it would be released publicly.

Julian, in remarks echoed by other American officials in recent weeks, said the Farah attack showcased a new Taliban tactic deliberately designed to create an outcry that would take American airstrikes off the table. U.S. forces have long claimed that enemy fighters use "human shields" to prevent soldiers from returning fire.

But this time, the insurgents actually wanted the Americans to attack so civilians would die, Julian said. The enemy fighters even had plans to kill the civilians themselves if the airstrikes didn’t kill enough people, allegedly by using grenades to make it look like bombs killed them, Julian said.