Inside a dilapidated Iraqi warehouse, the pine coffins are stacked five high. White sacks lie on the ground, lettered in Arabic. They contain more bodies. Altogether, U.S. military investigators said today, there are 664 coffins and 408 sets of human remains here.

Startled British officers from an artillery unit stumbled upon the makeshift morgue Saturday morning, when they moved in their 155mm guns to fire on holdout Iraqi fighters in the nearby city of Basra. At first, they believed they might have turned up a major atrocity by President Saddam Hussein's government.

But by this afternoon, as the artillery blasted away at Basra, investigators from a special task force, set up to hunt weapons of mass destruction and other possible violations by Hussein's government, announced a different finding. The bodies, they said, appeared to be soldiers killed in the Iran-Iraq war of 1980-88, stored here as part of a repatriation agreement between the two countries.

Chief Warrant Officer Dan Walters, an Army criminal investigator, said that the remains appeared to date from the mid-1980s and that those examined so far "seemed to be consistent with combat deaths, not a war crime."

In a second warehouse, there were catalogues and stacks of documents listing the names and nationalities of those lying here. From that, Walters said, investigators have concluded that about 85 percent of the remains are those of Iraqis and the rest are Iranians.

Outside the warehouse, a bullet-riddled wall also turned out to be less than the initial reports had suggested. "A search of the area did not reveal any evidence that the wall was used as a firing wall or an execution wall," Walters said.

For the special unit -- the 75th Exploitation Task Force -- sent here this morning by helicopter to check out the site, it was another search that did not yield the expected result.

The team has searched a number of sites in recent days. They included an air base at Tallil reported to contain chemical weapons, but which apparently did not, and an industrial site south of Baghdad where thousands of boxes of white power believed to be a nerve agent antidote turned out to be an explosive.

"Exploitation is more than just weapons of mass destruction," said Col. Richard McPhee, commander of the 75th Exploitation Task Force. "We are here to see if there were any abuses detected or human rights violations."

The investigation began here on the northern outskirts of Zubair, in a grim industrial area near an oil refinery, when a British Royal Horse Artillery unit moved in Friday, taking over an abandoned Iraqi military position. "At first light" on Saturday, Capt. Jack Kemp and another officer found the abandoned warehouse with the bodies and quickly sent the information up the chain of command. Kemp, who called the find "just part and parcel of everyday soldiering," said he had never been convinced the bodies were evidence of a war crime.

"It could be a normal product of war fighting. It doesn't necessarily mean torture," he said. "Just because a wall's got bullet marks on it doesn't mean it's an execution wall."

The two warehouses are set back slightly from the artillery batteries set up by Kemp and his men. In one warehouse are several concrete-walled chambers containing tall, gritty stacks of file folders, documents and catalogues strewn about, and detritus from everyday life such as food cans, a teapot and a cot. A poster of Hussein still hangs on the wall.

The other contains the bodies and stacks of plain pine coffins. There are bullet holes in the windows and a stack of old tires at the far end of the otherwise empty hangar. "It's not like any mass graves I've seen before," said one British military police sergeant, taking in the sight for the first time this afternoon. "It's organized, certainly," said Lt. Col. Neal Peckham, a British military spokesman.

Walters, the Army criminal investigator, said British forces were canvassing the neighboring area in search of Iraqis who might be able to explain how the bodies came to be stored here. But for now, he said, the story is still being pieced together using the evidence on the scene.

Documentation, however, does not seem to be lacking. The catalogues, he said, list "all dead people in the facility by name, rank and nationality." And some of the bags examined by investigators have included not only human remains but also personal effects of the deceased, including wallets, uniforms, ID tags and even money, Walters said.

It is not clear what will happen to the remains after the investigation is completed. "Obviously, we're going to try to get the remains back to the families," Walters said, though it was not clear how or when.

A statement from Iran today appeared to confirm that the remains were from the Iran-Iraq war, which claimed hundreds of thousands of lives.

Brig. Gen. Mirfeisal Baqerzadeh, head of an Iranian committee to account for those missing in that war, said today that the International Committee of the Red Cross should "immediately take the bodies from the invading forces and hand them over to the Islamic Republic of Iran," according to state-run Tehran Radio.

U.S. Army investigators said 408 sets of human remains were found at the warehouse. Initially, there was suspicion that they might have been evidence of an atrocity by the Iraqi government.