Mexican archaeologists have found the remains of what appear to be four U.S. soldiers who died in 1846 during the Mexican-American war, the government announced on Thursday.

Experts said skull and bone measurements, as well as two half-dollar coins and other artifacts found at the site of the Battle of Monterrey in northern Mexico, indicate the bodies belong to U.S. war casualties.

Mexico's national archaeological agency said the skeletal remains were uncovered in digs between 1996 and April 2008 but were apparently not announced previously. The U.S. Embassy said it had no immediate information.

It has taken experts a long time to even tentatively identify the remains, in part because it had long been believed that the site contained the mass grave of Mexican casualties. No Mexican soldiers have been found at the site, said Rogelio Caballero, of the government's National Institute of Anthropology and History.

"There are plans on paper to perform DNA tests" on the remains, Caballero added. "Attempts are being made at identifying the soldiers' families and descendants."

He said many of the U.S. soldiers involved in the battle were from the states of Tennessee and Mississippi.

U.S. forces defeated Mexican troops in Monterrey, which was a fortified position at the time. The 1846-1848 war ended in a Mexican defeat that, along with Texas' independence struggle, cost Mexico half its territory.

The new discoveries offer hope that the casualties of a long-ago war _ both Mexicans and Americans _ may finally be repatriated.

"There are proposals ... to return the those individuals found so far to the United States, and for them to return those that they have from battles that took place in their country," the institute said in a press statement.