Donald Trump's proposal to ban asylum for certain undocumented immigrants has been attacked as "illegal" by human rights groups who say that asylum is a "lifeline" for those fleeing danger.

Under the new measures from the White House, undocumented immigrants arriving at the nation’s borders between ports of entry would no longer be able to legally apply for asylum. The move relies on emergency powers the president had previously invoked through the implementation of his “travel ban” involving people from several Muslim-majority nations last year.

Mr Trump's proclamation will effectively suspend the granting of asylum to migrants who cross the US border with Mexico illegally for up to 90 days, beginning on Saturday.

In a statement shortly after news broke of the policy shift, one of America's biggest civil rights groups, the American Civil Liberties Union (ACLU) said: “US law specifically allows individuals to apply for asylum whether or not they are at a port of entry.”

The group added, “It is illegal to circumvent that — by agency or presidential decree.”

By Friday afternoon, the ACLU had filed a lawsuit against the directive, likely paving the way for an exhaustive legal battle.

Mr Trump has railed against undocumented immigration along the US-Mexico border since the start of his presidential campaign - but it has intensified in recent weeks with a number of caravans containing thousands of refugees and migrants slowly heading to the border. many of those travelling in the caravans are fleeing violence in Central American nations including Honduras and El Salvador.

The president recently proposed a slate of hardline policies to deal with the issue, including revoking the nation’s amendment-protected practice of providing birthright citizenship. The president has also called for housing immigrants in “tent cities”

On Friday, the president told reporters he had signed the directive to revamp the asylum process, effectively barring undocumented immigrants who cross the border illegally from applying for asylum.

The Independent goes on a ride-along with US Border Patrol Show all 15 1 /15 The Independent goes on a ride-along with US Border Patrol The Independent goes on a ride-along with US Border Patrol Texas and Mexico are connected by entry points like these. US Border Patrol in Laredo, Texas conducts daily patrols throughout the Rio Grande, snaking between the US and Mexico, where it searches for migrants and drug traffickers. The legal entry point to Mexico can be seen above the riverines frequently used by cartels to funnel narcotics into the US. Chris Riotta The Independent goes on a ride-along with US Border Patrol US Customs and Border Protection oversees its side of the entry point. US Customs and Border Protection officers oversee the processing of nearly two million trucks and three million pedestrians annually at the Laredo sector, which also processes the majority of trade between the US and Mexico. Chris Riotta The Independent goes on a ride-along with US Border Patrol The Rio Grande snakes between Mexico and the United States. The US and Mexico have bordering coastlines in Laredo Texas, where the Rio Grande's occasionally rough currents splash onto both nations' shores. For migrants attempting to enter into either country, the swim is much more dangerous than it appears. Chris Riotta The Independent goes on a ride-along with US Border Patrol Drug traffickers and migrants use "highways" to cross the border. US Border Patrol agents call worn pathways like these "highways," as they are frequently used by drug traffickers and migrants entering into the US. Chris Riotta The Independent goes on a ride-along with US Border Patrol The journey is still far from over. If they're able to make it onto land, many obstacles still remain for migrants and drug traffickers. US Border Patrol agents are equipped with high-tech security, K-9 units and aerial camera footage surveilling 40 miles of borderlands. Chris Riotta The Independent goes on a ride-along with US Border Patrol Border Patrol uses classic methods and high-tech to surveil the border. A control room at the Laredo sector headquarters is fully-manned 24/7 with a team of local employees who alert agents on the ground of border crossings in real-time. Their cameras live-stream 40 miles of the 170 mile territory the sector covers. Chris Riotta The Independent goes on a ride-along with US Border Patrol The US provides trusted traveler programs on both its southern and northern borders. Officers lead the way to Sentri offices, which runs a trusted traveller program from US and Mexican local residents who regularly cross the border for work or leisure purposes. Chris Riotta The Independent goes on a ride-along with US Border Patrol The pathway to freedom. Once travellers are processed, they walk up this ramp towards the US. Many Mexicans cross the border each day with collapsable shopping carts to buy goods while visiting the country. Chris Riotta The Independent goes on a ride-along with US Border Patrol But first, the wait. A dog waits for their owner to go through processing with US Customs and Border Patrol. On a good day, processing can take under an hour. On a bad day, well, there's just no telling how long one might be stuck inside the Laredo sector field offices. Chris Riotta The Independent goes on a ride-along with US Border Patrol The first lady of CBP. Inside the Laredo field offices, US Border Patrol agents keep a framed photo of Christine Davis, the first female agent to join the federal agency in 1975. Chris Riotta The Independent goes on a ride-along with US Border Patrol "The hall of fame." US Border Patrol also honors those who have served in the agency for over thirty years. Chris Riotta The Independent goes on a ride-along with US Border Patrol Officers inspect a vehicle in secondary processing. Outside, officers are conducting secondary inspection on a vehicle that's been pulled aside for further investigating. Chris Riotta The Independent goes on a ride-along with US Border Patrol The waiting room for detained migrants. A US Customs and Border Protection officer shows the inside of a holding room where people requiring further questioning go through secondary processing. Chris Riotta The Independent goes on a ride-along with US Border Patrol A man and his daughter go through processing. US Customs and Border Protection also regularly provides humanitarian visas and other temporary permissions for people with valid reasons seeking entry to the US. Here, a father and his daughter await to see whether they will be provided one of those visas. Chris Riotta The Independent goes on a ride-along with US Border Patrol Laredo processes over three million pedestrians annually. Thousands of legal asylum seekers, migrants and refugees seek entry to the US through the southern border annually, where they go through processing at offices like this after arriving at a legal port of entry. For many, the trip can take days, if not weeks or even months. Chris Riotta

Current law provides a year for migrants who have illegally crossed the border to apply for asylum, however, under the new orders migrants are required to go directly to a port of entry along the border in order to apply.

The UN refugee agency, UNHCR, said on Friday that everyone fleeing violence or persecution should get protection "without obstruction".

Many of the people on the move in Central America and Mexico today are fleeing “life-threatening violence or persecution” and require international protection, the UNHCR said in a statement issued in Geneva.

“UNHCR expects all countries, including the United States, to make sure any person in need of refugee protection and humanitarian assistance is able to receive both promptly and without obstruction in accordance with the 1967 refugee Protocol to which the United States is a party,” the agency said, referring to a protocol to the 1951 Refugee Convention.

It added that “long-standing insufficient reception capacity at official U.S. southern border ports of entry” was causing significant delays in northern Mexico, forcing many desperate asylum-seekers to turn to smugglers and cross the border irregularly.

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“National security and dignified reception of refugees and asylum-seekers are not mutually exclusive, but rather mutually reinforcing,” it said.

Human rights group Amnesty International also rejected the new measures and claimed it “needlessly places the lives of thousands of people in danger.”

“Asylum is not a loophole, it is a lifeline,” Secretary General Kumi Naidoo said.

The White House has defended the new measures, claiming the policy will make it safer for migrants who attempt to cross the geographically arduous border.