A new report paints a harrowing picture of what its like for thousands of migrants arriving to the US-Mexico border, as Donald Trump defends the use of tear gas against women and children in the region.

The report, released by Amnesty International UK and titled Americas: Stuck at the door, features interviews with 200 migrants who have travelled in caravans headed towards the border, alleging unlawful US immigration policies that have left thousands of asylum-seekers stranded in Mexico.

Amnesty found nearly 4,320 people were listed on an unofficial asylum wait list maintained by asylum-seekers themselves and Mexican officials at the Tijuana side of the San Ysidro port of entry. According to the international human rights organisation, “multiple sources in the Mexican government confirmed that Mexican immigration officials routinely coordinate with the US border authorities over how many asylum-seekers from the list will be received each day.”

Mexico’s immigration laws state authorities cannot restrict the flow of asylum-seekers exiting the country and travelling towards the US border.

“If Mexico agrees to do the US government’s dirty work at the expense of the caravan members’ dignity and human rights, it is effectively paying for Trump’s shameful border wall,” Erika Guevara-Rosas, Amnesty’s Americas director, said in a statement sent to The Independent.

She added, “The governments of Mexico and Central America must take urgent action to ensure they do not suffer further human rights violations.”

As a result of the extended waiting times in Mexico, thousands of migrants are at risk of deportation, with dozens of caravan members being detained by municipal police in Tijuana and eventually deported.

The report also describes “squalid” conditions migrants face, with Mexican officials reportedly admitting temporary shelters built to accommodate the influx of migrants “lacked sufficient food, water and health services, and that respiratory illnesses were spreading among those there.”

Meanwhile, Mr Trump claimed the tear gas recently used on women and children at the US-Mexico border was "very safe," walking back initial denials about border patrol agents using force against minors.

Trump defends use of tear gas

Speaking with reporters in Mississippi amid a campaign event for Senator Cindy Hyde-Smith, the president questioned why the migrants were arriving to the nation’s border, calling the women “grabbers” and claiming they “grab a child because they think they’ll have a certain status by grabbing a child.”

“Why is a parent running up into an area where they know the tear gas is forming and it’s going to be formed and they’re running up with a child?” He said, while adding the tear gas used was “very safe”.

Mr Trump appeared to echo claims made by Ron Colburn, the former deputy chief of US Border Patrol, who said on Fox News Monday morning the tear was “natural,” adding, “You can actually put it on your nachos and eat it. So, it’s a good way of deterring people without long-term harm.”

The president also appeared to directly contradict statements he made just hours earlier before flying to Mississippi, when a reporter asked him at the White House if he considered it “OK to use tear gas on children”.

“We didn't,” Mr Trump responded. “We don’t use it on children.”

Migrants clash with authorities as they seek to cross the US border Show all 23 1 /23 Migrants clash with authorities as they seek to cross the US border Migrants clash with authorities as they seek to cross the US border A group of migrants climb the US border fence in Tijuana AFP/Getty Migrants clash with authorities as they seek to cross the US border A group of migrants cross the dried up Tijuana river AFP/Getty Migrants clash with authorities as they seek to cross the US border Mexico police emerge from a cloud of tear gas Reuters Migrants clash with authorities as they seek to cross the US border Mexico police work to keep migrants from getting over the border with the US AP Migrants clash with authorities as they seek to cross the US border US border patrol agents stand guard as migrant seek to cross the border at Tijuana Reuters Migrants clash with authorities as they seek to cross the US border Adults help a child over the US border fence AFP/Getty Migrants clash with authorities as they seek to cross the US border Migrants near the US border in Tijuana Reuters Migrants clash with authorities as they seek to cross the US border Migrants climb the US border fence in Tijuana AFP/Getty Migrants clash with authorities as they seek to cross the US border Migrants clash with riot police as they near the US border in Tijuana Reuters Migrants clash with authorities as they seek to cross the US border A migrant is detained by US border patrol officers after illegally crossing the border Reuters Migrants clash with authorities as they seek to cross the US border A group of migrants cross the dried up Tijuana river Reuters Migrants clash with authorities as they seek to cross the US border Tear gas is deployed at the border Reuters Migrants clash with authorities as they seek to cross the US border A group of migrants make their way to the US border fence Reuters Migrants clash with authorities as they seek to cross the US border A migrant man wears a homemade gas mask Reuters Migrants clash with authorities as they seek to cross the US border Migrants stand on the banks of the Tijuana river opposite the US border fence Reuters Migrants clash with authorities as they seek to cross the US border A group of migrants cross the Tijuana river Reuters Migrants clash with authorities as they seek to cross the US border Migrants gather at the border crossing in Tijuana AP Migrants clash with authorities as they seek to cross the US border Tear gas is fired by border police to deter migrants EPA Migrants clash with authorities as they seek to cross the US border A migrant covers his face as tear gas surrounds him Reuters Migrants clash with authorities as they seek to cross the US border Migrant families seek to cross the US border at Tijuana Reuters Migrants clash with authorities as they seek to cross the US border Mexico police try to stop migrants from crossing Reuters Migrants clash with authorities as they seek to cross the US border Migrants force their way through the border fence at Tijuana Reuters Migrants clash with authorities as they seek to cross the US border Migrants, part of a caravan of thousands traveling from Central America en route to the United States, run across the Tijuana river to reach the border wall between the U.S. and Mexico in Tijuana, Mexico November 25, 2018. REUTERS/Alkis Konstantinidis TPX IMAGES OF THE DAY Reuters

By the time the president landed in the south to campaign for Ms Hyde-Smith — whose re-election was once considered a sure-fire victory for the Republican Party, until her controversial statements and history with race relations came to light — it was clear those denials would no longer hold up.

US Customs and Border Protection confirmed agents made the decision to use their professional judgement and fire the tear gas at migrants, with CBP Commissioner Kevin McAleenan saying the agents were mostly reposing to adult males who threw rocks at US officials.

Migrants have revealed harrowing accounts of what it was like to be hit tear gas at the border this week, including Cindy Milla, who told the Wall Street Journal, “I felt that my face was burning, and my baby fainted.”

She added, “I ran for my life and that of my children.”

Still, the Trump administration continued to assert the use of force was necessary, following the president’s admittance Monday night.

Department of Homeland Security Secretary Kirstjen Nielsen claimed without evidence in a Facebook post Monday night that “It appears in some cases that the limited number of women and children in the caravan are being used by the organisers as ‘human shields’ when they confront law enforcement”.

Ms Nielsen also claimed without evidence “the caravan members are predominately male,” warning parents “to avoid violent caravan groups and refrain from attempts to illegally enter our country.”

Support free-thinking journalism and attend Independent events

“These acts will put your children in danger,” she wrote.

In its report, Amnesty issued 26 recommendations for the US and Mexican governments, urging officials ensure human rights protections for all migrants crossing the border, as well as to supply humanitarian support for asylum-seekers.