WASHINGTON - The Pentagon said yesterday that U.S. troops did not follow proper tactics and procedures during an air assault last month on Taliban fighters that also killed a number of civilians.

Pentagon spokesman Geoff Morrell said the number of Taliban extremists killed in the May 4 air strikes "greatly outnumbered" the number of civilians slain. But Morrell noted some problems in the way the strikes were carried out, citing a U.S. warplane that investigators said did not follow proper procedures.

Defense Secretary Robert M. Gates was briefed yesterday on the results of a classified U.S. Central Command inquiry into the air strike, but Pentagon officials were not elaborating on the findings.

The report analyzes only the May 4-5 incident and makes no wider observations about the use of bombing aircraft or unmanned drones to launch air strikes in Afghanistan, a military official familiar with the report said. The official, who spoke on condition of anonymity because the document is still classified, said it did not recommend disciplinary action for U.S. personnel involved.

"There were some problems with some tactics, techniques, and procedures, the way in which close air support was supposed to have been executed in this case," Morrell told reporters at a Pentagon news conference.

It appeared that a B-1 bomber "because of how it takes its bombing routes, has to break away from positive ID of their target at one point," he said.

"There's no way to determine whether or not that had anything to do with the fact that civilian casualties did occur in this incident, but they [investigators] did note that as one of the problems associated with how this all took place."

Afghan officials have said the civilian toll was 140 dead. U.S. commanders have said they believe no more than 30 civilians were killed, along with 60 to 65 insurgents.

Yesterday, Morrell would not discuss the inquiry's conclusion about how many civilians died, "but they were greatly outnumbered by the Taliban killed in this incident," he said.

According to the U.S. military, the battle in Farah province began a day after Taliban fighters entered two villages, demanded money from civilians, and killed three former government employees. An Afghan force rushed in and was ambushed by as many as 300 insurgents.

The provincial governor asked for U.S. military help, and ground troops joined the battle, the U.S. officials said.

Before the battle was over, troops called in F-18 fighter-jet air strikes as well as help from the B-1 bomber, coordinating with the ground commander to hit a half-dozen targets, including buildings and a tree grove that insurgents were firing from or massing in, U.S. officials have said.

Although the United States is expected to change some military tactics as thousands of additional forces arrive in the areas of heaviest fighting this summer, officials have been clear that they will not abandon aerial strikes. Rules for using them have been tightened over the past year.

Gates' new military managers for the war could be on the job as early as this week. Gates fired the top U.S. general in Afghanistan in May, in part out of frustration that he did not move quickly enough to apply counterinsurgency lessons learned in Iraq.

Gates wants his new leaders to do an immediate 60-day review of the war, with an eye to changing some ground-level operations, Morrell said yesterday.

Gates will get a closer view of widening U.S. operations this week when he meets with defense ministers from other troop-contributing countries and with NATO ministers.