Iraqi villagers accused U.S. forces of killing five civilians this week during a bloody hunt for Saddam loyalists (search). The operation was the largest of its kind since the war ended.

Farmer Jaafar Obeid, told The Associated Press that a 70-year-old relative as well as four other male relatives, were shot by troops who allegedly mistook them for fleeing militants.

Lt. Col. Greg Julian, a U.S. military spokesman, declined to comment on reports of civilian casualties in the incident, which started late Thursday on the outskirts of Balad (search), a rural area 30 miles north of Baghdad.

"If they're wearing civilian clothing and shooting weapons at you, they are not classified as civilians," Julian said Saturday.

But townspeople said the five men were trying to douse fires in their wheat fields set by U.S. flares when soldiers shot them. Mourners set up three tents for funeral services in Elheed, the village near Balad where people said the men were killed.

Obeid said an American officer came and apologized to the family Friday morning for the deaths, which he said have devastated the village.

"This action will bring harm to them (the Americans)," the farmer said. "They should have checked before opening fire. They have eliminated a whole family."

The ambush near Balad started just before midnight Thursday, when a large force of insurgents detonated a land mine and fired rockets on a two-tank patrol of the 4th Infantry Division, said Lt. Col. Andy Fowler, a senior officer.

The tanks returned fire, killing four assailants, before calling in reinforcements including Apache helicopters and Bradley armored vehicles and chasing the fleeing attackers, U.S. Central Command said.

There were no American casualties but conflicting reports of Iraqi deaths. U.S. Central Command said American forces killed 27 Iraqi insurgents but officers at the scene put the number much lower, at five or seven.

The tank ambush appeared to be part of a growing campaign of violent resistance to the U.S. occupation of Iraq. Fighting intensified this week to its highest pitch since the war was declared over May 1 and was likely to escalate as U.S. forces press their crackdown on anti-American forces.

The operation, concentrated in areas north and west of Baghdad, targets what Central Command described as "Baath Party (search) loyalists, paramilitary groups and other subversive elements."

Hundreds of people have been detained for interrogation in the sweep, which has triggered widespread anger among Iraqi townspeople over the heavy-handed tactics of American soldiers. By Saturday, all but a few of the detainees had been released.

American troops came under two separate grenade attacks in the northern city of Mosul on Friday, though no casualties were reported, said Lt. Col. Julian, a U.S. military spokesman. Unknown assailants hurled grenades at a joint coalition-Iraqi police patrol and at a foot patrol of U.S. forces.

Strategists said the U.S. military has been preparing to strike the remnants of Saddam's fighting forces since the end of the war, gathering intelligence on their whereabouts and capabilities.

U.S. soldiers, hunkered inside thick armor and equipped with computer-guided weapons, have been running obtrusive patrols, hoping to taunt insurgents into action and lure them into the open where they would be overwhelmed by the superior American weaponry.

"We will maintain that pressure, causing him to react to us, rather than vice versa," said Lt. Gen. David McKiernan, U.S. ground forces commander in Iraq. "Are there bad guys still out there? Absolutely. Are we going after them? Absolutely."

For weeks, American forces have been targets of hit-and-run attacks, usually by individuals or small groups throwing grenades, or firing rockets or small arms, and then fleeing. Forty-nine U.S. soldiers have died in Iraq since May 1, according to the U.S. Central Command.

On Saturday, a U.S. deadline expires for Iraqis to turn in weapons, often kept in homes for protection against the looting and banditry unleashed in the chaos after the American invasion of Baghdad.

So far, an array of arms has been handed in — 152 anti-tank rocket launchers, 11 anti-aircraft weapons and hundreds of assault rifles and handguns — but it was only a fraction of the weapons remaining in Baghdad's streets.

Iraqi and U.S. military police said Saturday that few Iraqis were handing over weapons because of the fragile security situation.

"In the past two weeks, we've had no more than two pieces of arms handed in," said Adnan Abbas, an Iraqi warrant officer at the Balat al-Shuhada police station. "An old Iraqi man walked in today with a hunting rifle and we told him to take it home," he said.

Lt. Derek Wilson, with the U.S. military police unit that controls Balat al-Shuhada, acknowledged the slow pace of the handover and said U.S. forces will have to respond.

"After today, we will pursue an aggressive policy," he said, without elaborating.

The Associated Press contributed to this report.