SARIC, México - On the baked sands of northern Mexico, barefoot tribeswomen chant and dance in clouds of incense, calling on the eagle to save them from US President Donald Trump's border wall.

The US-Mexico frontier runs through more than just the deserts of Sonora and Arizona. For the Tohono O'odham with their eagle totem, it divides their people.

These are their ancestral lands, a nation that was here thousands of years before the modern states of America and Mexico were drawn on the map in the 19th century.

"This is our land," says tribal elder Alicia Chuhuhua, 80, at the ceremony among the looming cactus plants, speaking in the tongue of her tribe through a Spanish-language interpreter.

"We want it without 'muros'," walls, she says, using the Spanish word -- in her indigenous tongue, there is no term for "wall" or "border."

        - Desert life -

The 3,000 strong Tohono O'odham population -- the name means "desert people" -- is recognized as an indigenous nation in the United States.

Most of them live on the US side of the border in the town of Sells, Arizona, with a few hundred estimated to live in Mexico.They are allowed to cross to and fro through the San Miguel Gate, for funerals on the Mexican side, for example, or for medical treatment in Arizona.Chuhuhua remembers living a semi-nomadic life as a girl. In her day, the Tohono harvested dragon fruit and made cactus syrup.

Just a decade ago, there was still a bus that took Tohono children from the Mexican state of Sonora across to Sells for school.But one by one, border crossings have been closed to them. Only San Miguel remains as a free transit point within reasonable distance.Now they fear that too will be blocked when Trump builds the wall.

He says it will stop illegal migrants and drugs reaching the United States.But Chuhuhua and her fellow Tohono O'odham say it will break apart their ancestral land.

If forced to go via another, more distant border crossing, "we would waste more than seven hours going all the way round," says Gemma Martin, a Tohono woman living on the Mexican side. "What do we do if it is a medical emergency? By the time we get there it may be too late."

     - Human rights -

Tohono leaders plan to take their claim against the wall to the United Nations along with other Native American tribes, said one of them, Mike Wilson.He served in the US Army and is now a human rights activist.

"The new version of the wall would be even worse," says Wilson, in cowboy boots and a grey ponytail.

"It is a form of human rights violation," he says, because it would deny freedom of movement to members of a tribe on their own territory.The Mexican government has also promised to support a case the tribe is planning to file next month at the Inter-American Court of Human Rights.

- Divided hearts -

Even before the wall has been built, however, the Tohono O'odham are divided among themselves.he tribe's vice-president Verlon Jose told reporters he would see the wall built "over my dead body."But others have cast doubt on his stance.

David Garcia, a former member of the Tohono Supreme Council, says some in the tribal leadership are reluctant to oppose Washington for fear of losing US subsidies.Faith Ramon, a Tohono student of 34 from Arizona, says tribal authorities tried to stop her traveling to Sonora for the ceremony.

"I feel hurt by my own tribal leaders," she said. "We need to stop using that green paper," the dollars of subsidies, she said.Jose did not respond to AFP's requests for comment.The Tohono women finish their dance under the burning desert sun.

As the sky turns red at sunset, they head back to their homes -- and an uncertain future -- either side of the border."It cuts our heart in half. Half of our heart is in Sonora, the other half in Arizona," Wilson told AFP.

"You can't be whole if you have your heart cut in two. The heart must be one, closed, and living and surviving together."-AFP