NACO, Ariz (Reuters) - The two towns are both called Naco: one lies in Mexico, the other in the United States. But when it comes to fighting fires, it is all one community.
When a blaze breaks out south of the international line, fire chief Jesse Morales and his crew of volunteer fire fighters pull on their gear, pile into a Ford fire truck and head to border point.
Weaving through the gate with their lights flashing, they are met by a Mexican police escort and set off to fight fires in the neighboring town in what may be a unique instance of cross-border cooperation between Mexico and the United States.
Many towns and cities the length of the U.S.-Mexico border have strong civic ties across the line, although no other fire brigade is believed to regularly cross the border to tackle fires.
The towns, which lie in a remote high desert valley some 100 miles southeast of Tucson, Arizona, have a combined population of fewer 9,000 people.
Almost all of the dozen members of the Arizona fire crew have family in the dirt-poor ranching town in Sonora, Mexico, where some residents live in homes knocked up from wooden pallets and plastic sheeting.
"If someone's house catches fire it might be the only thing they have in this world, so we try and get there as fast as we can," said Morales, 32, who has battled dozens of blazes over the line since becoming a fireman 15 years ago.
"Naco is one big community and we do not hesitate to cross and help them."
The two towns weathered the Mexican revolution together in 1914, when Pancho Villa and his pistoleros battled federal troops yards from the border line in Mexico.
Cooperation over fire-fighting began in 1959, the year that the volunteer fire department in the tiny Arizona town was formed, and has continued ever since.
The Arizona firefighters are on call around the clock. When they are summoned to fight fires in Mexico, they call the small port of entry to let U.S. Customs and Border Protection officials know they are heading south.
Later, the fire crew often come back to the old adobe U.S. Customs House to refill their water tanks at a fire hydrant beside the international line.
Recent blazes fought by the brigade have included a fire at the Mexican town's garbage dump that smoldered for a week, belching toxic smoke over both sides of the rusted border fence.
Another was a roaring inferno fanned by hot desert winds that engulfed three adjacent homes in the Mexican town, where many of the roads are unpaved.
They are joined by the eager, though desperately ill-equipped Mexican fire department, who have three aging fire engines dating from the 1950s and 1960s, none of which work.
"On one occasion, when we arrived there were four or five firemen, including the chief, with their thumbs over garden hoses trying to put out three fires," said assistant fire chief Jim Pionke.
"If it wasn't sad, it would be comical. They did everything they could, but they just didn't have the equipment," he added.
The aid has long been appreciated by residents of Naco, Sonora, not least by the president of the struggling fire department, housed in a low building a few blocks south of the small border crossing.
"We are very grateful to our neighbors," said Manuel Bravo, as he stood in the chill firehouse among the broken trucks. "We want to do something to help ourselves, but without the equipment, we can't."
The Arizona firemen's unusual service south of the line, which has won commendation from Ariz. Gov. Janet Napolitano, is not without controversy in the United States, where illegal immigration, border security and the subject of U.S. tax dollars spent on non-citizens are hot button topics.
In the past, tempers in Arizona have been easily inflamed by reports of illegal immigrants using health services and Mexican children crossing the line to go to school each day.
But Pionke, a recent transplant from Chicago and the only non-Hispanic member of the fire brigade, says the only cost of heading to Mexico is gas for the fire engine.
He believes if there was ever any need to do so, local people would reach into their pockets and pay that money to continue helping their neighbors in dire need south of the border, and remains quite clear about why they do it.
"It's the right thing to do. It's not about we're Americans and they're Mexicans, it's about humanity," he said.
"There will be a day when there are no borders. That day will come."
Reporting by Tim Gaynor; Editing by Eddie Evans