The order comes as thousands of Central American migrants continue their caravan trek through Mexico toward the hoped-for, but still far-distant USA border.
Worldwide law requires that individuals fleeing violence and persecution must be allowed access to the country where they are seeking asylum and the right to apply for it.
Observers have described it as "a river of people".
Under rain, people take cover at a makeshift camp set up by a caravan of Central American migrants traveling to the U.S, in Mapastepec, Mexico, Wednesday, Oct. 24, 2018.
He said Honduran President Juan Orlando Hernandez told him the caravan "was organised by leftist groups in Honduras financed by Venezuela and sent north to challenge our sovereignty and challenge our border". In fact, many immigrants said they'd be just as happy to stay in Mexico indefinitely if they were allowed.
Some specific statutes authorize the president to deploy troops within the United States for riot control or relief efforts after natural disasters. The number of migrants who unlawfully entered the US with a family member spiked in September as Trump cast immigration as a crisis.
While such caravans have occurred semi-regularly over the years, this one has become a particularly hot topic ahead of the November 6 midterm elections in the USA, and an immigrant rights activist travelling with the group accused Trump of using it to stir up his Republican base.
The Trump administration has not settled on a plan for what to do if a migrant caravan arrives at the southern border, despite threats by President Donald Trump to declare a national emergency or rescind aid from the countries whose people are journeying north.
One of the migrants held up a sign reading: "Emigrating is not a crime, let's be free without borders".
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The Prime Minister also said that the government was in contact with two other friendly countries for more financial assistance. However, it will be for one year in the form of cash assistance and oil on deferred payments.
Their arrival at the border would only begin another arduous journey, one that seems unlikely to end with many of them obtaining asylum. Thousands of them headed for the bridge dividing the two countries.
Mexican authorities insisted those on the bridge would have to file asylum claims one at a time in order to enter the country. Mexican police have not tried again to stop them. He's paralyzed and looking for work and better doctors in the U.S. He said he doesn't even have any shoes, since he gave them to his friend.
With those on the Guatemalan side of the bridge growing increasingly frustrated at the wait, tempers flared and the two sides clashed, with some migrants throwing stones and police firing tear gas.
One of the men fell off a truck in Mexico, and the other died trying to get onto a truck in Guatemala, authorities said.
The relief of those who made it into Mexico was great.
Locals have been helping the migrants.
However, catching lifts in overcrowded lorries and SUV can be risky.
The UN Refugee Agency is also monitoring returns and deportations from Guatemala, to ensure that they are voluntary and respect the fundamental principle of non-refoulement.
Of those 1,500, only about 250 legally remain in the US pending an immigration hearing, according to Pueblos sin Fronteras, a humanitarian aid organization for migrants.