WASHINGTON — An initial American military probe supports allegations that American Marines deliberately shot 24 Iraqi civilians in Haditha last November, a Pentagon official said yesterday.

The Marine Corps and Navy prosecutors are now reviewing the evidence to determine whether to recommend criminal charges. That decision may be weeks away, and the lawyers may ask investigators to probe further, two officials said.

They discussed the matter on condition that they not be identified because the case — among the most sensational of several involving Iraqi civilian deaths — has not yet produced charges.

Ed Buice, a spokesman for the Naval Criminal Investigation Service, which is leading the probe, said: “It’s fair to say that the majority of the work has been done. But it’s impossible to predict how much longer the investigation will take. It is very much open and ongoing.”

The case is open because prosecutors and officers in the chain of command of the Marines being investigated may consult with the naval investigation service even after any charges are brought.

A decision on whether to press charges ultimately will be made by the commander of the Marines’ parent unit, the 1st Marine Expeditionary Force at Camp Pendleton, Calif. Currently, that officer is Lieutenant General John Sattler, but he is set to move to a Pentagon assignment soon. His successor will be Lieutenant General James Mattis.

Investigators conducted a wide range of interviews with Marines in Iraq and with Iraqis in Haditha, but they failed to obtain permission to exhume the bodies of the 24 who were killed, two officials said. Nonetheless the probe did collect evidence from the Marines and from the scene of the killings.

The case is one of several involving allegations of unjustified killings of Iraqi civilians that have emerged this year, damaging the American image abroad and triggering calls by some Iraqi leaders to end the arrangement under which American troops are immune from prosecution by Iraqi authorities.

The Marines initially reported after the November 19, 2005, killings at Haditha that 15 Iraqi civilians had been killed by a makeshift roadside bomb and in crossfire between Marines and insurgent attackers. Based on accounts from survivors and human rights groups, Time magazine reported in March that the killings were deliberate acts by the Marines.

The top Marine commander in Iraq, Major General Richard Zilmer, then ordered a criminal investigation.

A parallel investigation is examining whether officers in the Marines’ chain of command tried to cover up the events.That probe, which has not been made public, faults some officers for failing to pursue discrepancies in the initial reports about what happened in Haditha and for not launching an early investigation.

When asked about the matter at a news conference yesterday, the chairman of the Joint Chiefs of Staff, Marine General Peter Pace, said the cover-up probe’s report was 3,000 to 4,000 pages long and being reviewed by the top commander in Iraq, Army General George Casey.

General Pace described the criminal investigation as “ongoing” and said it would remain so until military authorities have reviewed its results as well as the findings and recommendations of the cover-up probe “to make sure that every single possible cross-thread has been looked at.”

Among the other recent cases of alleged deliberate killings of Iraqi civilians, seven Marines and one Navy corpsman have been charged with premeditated murder and other criminal acts in connection with the killing of an Iraqi man in Hamdania on April 26. Also, five soldiers and a former soldier have been charged in the alleged March 12 rape and slaying of a 14-year-old Iraqi girl and the killings of her relatives in Mahmoudiya.