Green Valley, Arizona - Shura Wallin shuffles through a stack of drawings given to her by migrant children. She finds the one she is looking for and lifts it up. It depicts a Border Patrol vehicle chasing three stick figures, their arms raised as they flee.

Each week, Wallin and other humanitarian volunteers set out for some of the most dangerous corridors in the southern Arizona desert, leave out water jugs for migrants and refugees and search for the remains of those who died along the way.

Wallin, a 77-year-old retiree, co-founded The Green Valley-Sahuarita Samaritans along with Pastor Randy Mayer in 2005 in response to the dire humanitarian conditions migrants and refugees face crossing the United States-Mexico border.

Today, the group has around 350 volunteers. And for the last 15 years, the volunteers have provided medical aid, humanitarian supplies and medicines for desperate people fleeing violence and economic catastrophe.

Since she started working on the border in 2000, Wallin has found severely dehydrated people, others with thrashed feet - having worn through their shoes during the journey - and recently deceased bodies.

Throughout her nearly two decades on the border, undocumented migrants and others crossing the border have been pushed into desperate situations.

"When we first got started, we found an awful lot of people out in the desert," Wallin tells Al Jazeera. "The routes have changed dramatically; the routes are more dangerous now. It's much, much more dangerous than it was in the past."

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But now, as US President Donald Trump escalates his crackdown on asylum seekers and undocumented immigrants, she says that humanitarian workers and volunteers are struggling to work in an increasingly hostile political climate.

"There are more challenges for not only people who those of us who are trying to save the lives of people, but definitely [there are increased] challenges for people who are trying to come across," she says.

"When I listen to the rhetoric that spews forth from so many people, I think they don't have a clue of why people are having to flee."

Last month, key parts of the US government shut down after Trump refused to back down over his demand for more than $5bn in funding for a wall on the US-Mexico border. Three weeks later, Trump stands firm on his demand, threatening to declare a national emergency to get the wall built.

In mid-October, as a US-bound caravan of mostly Central Americans made its way towards the southern border, Trump falsely claimed that the US was facing an impending "invasion". That same month, he deployed thousands of US troops to border areas.

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Facing a swell of criticism, the Trump administration has lashed out at Democrats and pro-migrant groups. "Our system has been pushed to a breaking point by those who seek open borders," Secretary of Homeland Security Kirstjen Nielsen said last month.

"Smugglers, traffickers and their own parents put these minors at risk by embarking on the dangerous and arduous journey north."

'Obama did the same evil things. Trump relishes it.'

Joel Smith, the operations manager at the Tucson-based Humane Borders nonprofit, started working on the border in 2009. In the last decade, he has witnessed migration routes change "drastically".

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As Border Patrol set up shop in safer corridors along the frontier, migrants and refugees were pushed into more challenging pathways into the US, he tells Al Jazeera. "Obama did the same evil things, but Trump just relishes in it."

According to the United Nations migration agency, the number of people who died on both sides of the US-Mexico border increased from 398 in 2016 to 412 in 2017, even as border crossings decreased.

"The risk now is more than ever," Smith says.

But as Trump turns the border into a keystone of his administration's agenda and risks for border-crossers soar, Smith has observed a larger number of people reaching out to help in humanitarian operations.

About 95km south of Tuscon, in Arivaca, Arizona, Dan Kelly stands on his back porch. He can see the mountains straddling the US-Mexico border only 19km away. By car, he can reach the frontier in half an hour.

But for migrants and refugees passing through that corridor, the risks are plenty: inhospitable terrain, Border Patrol agents on the lookout, and surveillance drones watching from above.

"You can't live here and not see human suffering," Kelly, 73, tells Al Jazeera, estimating that nearly every week residents stumble upon travel-worn people who have crossed into the US.

Inspired by the work of humanitarian groups and activists across the region, Kelly plans to assemble a group of military veterans and cowboys to carry out water drops and other migrant relief efforts in the desert.

The 19km-stretch from the border to Arivaca is studded with cacti, wild animals, cavernous valleys and a wall of mountains.

"We know that it is physically impossible, say, to cross that 12 miles [19km] while carrying enough water to survive," Justine, an activist with No More Deaths, tells Al Jazeera, explaining that water drops could amount to the difference between life and death in the desert. Citing privacy, Justine declined to provide a surname.

Established as a coalition of faith and community groups in 2004, No More Deaths seeks to alleviate the suffering endured by people crossing the border and the desert.

Like other humanitarian groups, its volunteers leave out water jugs in many of the least hospitable corridors of Southern Arizona's desert, search for those who go missing along the way, and document human rights violations by Border Patrol and other authorities.

'Suffering, death and disappearance'

In January 2018, No More Deaths released a video of Border Patrol agents dumping out water jugs left behind by humanitarian groups. In a report that accompanied the clip, which included footage from as early as 2011, the group accused authorities "condemn[ing] border crossers to suffering, death and disappearance".

In a statement at the time, Border Patrol said it was aware of the video and that its agents "have been instructed not to remove or destroy water stations, food or other resources left along trails in the desert".

In December 2017 and January 2018, authorities dealt criminal charges to nine activists in relation to their humanitarian work in the borderlands.

Among those charged was Scott Warren, a 36-year-old No More Deaths volunteer, who is accused of harbouring undocumented immigrants last January as part of a human smuggling operation.

Authorities have also charged Warren with misdemeanours over his leaving behind water, food crates and humanitarian supplies on the Cabeza Prieta National Wildlife Refuge in June 2017.

Eight other No More Deaths activists were charged with entering a wildlife refuge without a permit after they carried out humanitarian operations on the territory in July and August of 2017.

Earlier in the year, US Fish and Wildlife Service introduced new regulations on permits that bar individuals or groups from leaving out food, water, blankets and medical supplies.

Back in her home, Shura Wallin lifts a photo showing a migrant's battered and bloody feet. While walking through the desert, he had worn through the soles of his shoes.

"What percentage of people do you know who want to leave their families and their countries? I don't know anybody," she says.

When Wallin hears the rhetoric coming from the White House and opponents of immigration, she poses a question.

"Why don't you come and look into the faces of the people we are demonising and then tell me we're doing the right thing?" she asks.

"Because [as a country] we are not acting in a humanitarian way at all, other than the groups trying desperately to save the lives of people."