Their race against Trump
Migrants in Mexico rushing to enter the US before president-elect takes office
SASABE, MEXICO: Migrants trying to sneak into the US from the parched Mexican desert have to contend with the border guards' drones overhead, poisonous snakes underfoot and human trafficking gangs at their backs.
But these are nothing compared to their bigger fear: that soon, US President-elect Donald Trump will build a wall to keep them out altogether.
So before Mr Trump takes office today (tomorrow, Singapore time), the migrants are racing against time, riding a freight train up to the border to look for a way across.
In Caborca town near the frontier, a group of Hondurans warm themselves by a fire of trash in the early morning cold.
One of them, builder Wilson, 48, missed the birth of his daughter to make the journey.
"When I saw that man on the television saying how he hated migrants and was going to build a wall, I thought: 'It's now or never," said Mr Wilson, who would not give his last name.
The Mexican authorities are arresting thousands, sometimes tens of thousands, of undocumented migrants each month, according to government figures.
Governors of several northern states this week called for extra resources to deal with the surge.
Meanwhile, local charity activist Laura Ramirez has been serving more than 200 free lunches a day to the migrants.
"There are more and more migrants coming," she said.
In the border town of Sasabe, marks in the rust on the border fence appeared to show a spot where migrants climbed over, said Mr Sergio Flores, leader of a government migrant task force.
"They have been getting sophisticated" in their efforts to get across undetected, he said.
Nearby lies a bottle of water, painted black - a common trick to stop the plastic from shining in the sun and catching the eye of the border guards.
The migrants wear soft-soled slippers so as not to leave footprints in the sand, along with camouflage clothes and masks.
Some even made soles for their shoes that make their footprints look like cows' hooves.
In their rucksacks they carry anoraks, remedies for snake bites, alcohol for lighting fires, talcum powder for their feet and painkillers.
They buy their supplies from shops in the town square of the local village of Altar - an area dubbed "Migrants' Wal-Mart."
The migrants had paid about $1,000 each to so-called "coyotes" - people traffickers - to bring them here from their native countries.
On arrival, some traffickers tell the migrants they must pay another $5,000 to get across the border.
Some who cannot pay the traffickers instead cross the border as drug "mules", with 50kg of marijuana on their backs.
"You have to bring your own water, food and blanket," said one such "mule".
"They don't pay us. The payment is being allowed to cross."
Just across the US border, in the town of Arivaca, Arizona, locals mistrust the migrants.
"We cannot deny that they bring trouble," said a waiter in the town, who asked not to be named.
"I just think they shouldn't be here. This is not their home." - AFP