Mexican soldiers carrying automatic weapons interrupted the Independence Day (search) funeral of a U.S. Marine and demanded that the Marine honor guard give up ceremonial replicas of rifles they carried. The move drew an angry reaction from the U.S. Ambassador.

Hundreds of friends and relatives packed a small cemetery for the funeral on Sunday of 22-year-old Juan Lopez (search), who was born in this sun-scorched farming town, immigrated to Dalton, Ga., as a teenager and became a Marine.

He was killed in an ambush in Ramadi, west of Baghdad, on June 21.

Maj. Curt Gwilliam presented an American flag to Lopez's widow, Sandra Torres, who clutched a bouquet of yellow and white flowers while tears streamed down her face.

While the funeral demonstrated the close human ties of Mexico and the United States, problems began moments after the start.

Four U.S. Marines marched solemnly to the grave carrying an American flag and the colors of the Marine Corps. Two of the men had rifles that looked real, but could not be fired, strapped to their backs.

Four Mexican soldiers blocked their path, asking the four Marines and six others who had served as pallbearers to return to the car that had brought them to the funeral. Several minutes of discussions by soldiers from both countries continued until a trumpet player began a rendition of taps and the funeral proceeded, despite the objections of the Mexican troops.

When the ceremony was complete, the Marines returned to a U.S. Embassy vehicle and waited. Fourteen Mexican soldiers arrived to guard the premises. About 40 minutes later, the Mexican soldiers allowed the van to leave.

"I'm outraged that this would take away from the ceremony honoring U.S. Marine Juan Lopez Rangel, whose family requested he be buried in his town of birth with full military honors," U.S. Ambassador Tony Garza said in a statement.

Mexico has a deep suspicion of foreign military forces in its territory. The Marine Hymn's "Halls of Montezuma" refers to the 1847 U.S. capture of Mexico City.

The Mexican Defense Department (search) banned plans for a 21-gun salute by Marines because Mexico's Constitution bans foreign soldiers from carrying firearms here.

Mexican soldiers at the funeral refused to comment, but U.S. Embassy spokesman Jim Dickmeyer said they likely saw the rifle replicas and mistakenly thought the Marines were planning to fire a salute anyway.

"These are ceremonial weapons," Dickmeyer said. "We were told not to bring M-16s, we didn't bring M-16s. We were told not to fire in the air, we didn't fire in the air."

Lopez's cousin, Octavio Lopez, called the interruption "a big mistake."

"If carrying these rifles was part of the ceremony, a ceremony the family wanted, how could it have been anything but positive?" he asked.

When U.S. Marines loaded Lopez's gray coffin onto a hearse earlier in the afternoon, a swell of local residents poured through the street and marched with the Lopez family past shabby brick homes.

A mariachi band dressed in green sang, "Goodbye for ever, goodbye." The music never stopped during a somber 45-minute march across town.

As church services began, about 300 people who could not fit inside listened over loudspeakers and sang along.

An hour later, several hundred people marched about a half mile to the ceremony to watch as Lopez's gray coffin was lowered into the ground.

Some of those who marched in Lopez's honor voiced opposition to the U.S.-led war in Iraq (search).

Lopez met his wife in Dalton and the couple married in December. Earlier in the day, Oscar E. Lujan, attache for U.S. Citizen and Immigration Services at the embassy in Mexico City, presented her with Lopez's American citizenship, which he earned following his death.