The migrant caravan from Central America is still hundreds of miles from the US border - here's everything we know about when it could arrive and what will happen next

• The main caravan of roughly 4,000 Central American migrants is steadily moving north towards the United States border - but it has splintered into groups and remains hundreds of miles away.
• There are some major unknown factors that make it unclear exactly when, where, and how the migrants will arrive at the US-Mexico border.

The caravan of some 4,000 Central American migrants who have been steadily trekking north towards the United States for weeks began to splinter on Saturday, following dashed hopes that they would be transported via bus to Mexico City.

Though the Trump administration has been brainstorming ways to crack down on border security and pressure Mexico to keep the migrants from progressing further, the caravan has largely persisted, though its numbers have dwindled in recent days and the dispute over the buses caused them to separate.

Earlier this week, President Donald Trump held a bizarre, rambling press conference in which he raged against the caravan and made a vague promise to bar immigrants from seeking asylum if they cross the border illegally, though it's unclear if such an action would pass legal muster.

Here's everything we know about the caravan and what could happen next:

Where is the caravan now and when will it reach the US?

Some of the migrants, downtrodden and exhausted, lashed out at organizers who had tried and failed to arrange the transportation, according to the Associated Press. Several thousand reached the towns of Juan Rodriguez Clara and Isla in Veracruz state, while others headed north to Tierra Blanca, Veracruz.

The group has been averaging between 20 and 30 miles per day thus far. They are mostly on foot, but have been hitch-hiking rides or piling into the backs of pickup trucks when possible.

It's unclear when exactly it will reach the US because the migrants have not said what route they're planning to take, or where along the 2,000-mile US-Mexico border they intend to cross, though they've been traveling closer along the Gulf coast in recent days, indicating they may aim for Texas.

Read more: Why the caravan of 4,000 migrants is marching to the US border

The nearest point to them would be in southeastern Texas, more than 700 miles away, but it's also possible the caravan could try to reach the San Diego, California, area more than 2,000 miles away, where a similar caravan ended up last spring.

Several other caravans have also sprung up in weeks, though they're smaller and further behind than the main caravan.

How is the Trump administration trying to stop it?

The Trump administration has been weighing a number of actions in recent weeks, and recently authorized a military deployment of more than 7,000 troops to the US-Mexico border.

Read more: Trump is sending thousands of troops to the border with Mexico - here's everything we know so far

Trump also announced Thursday he intends to dramatically limit the ways immigrants can seek asylum in the United States, and will seek to curb their ability to receive asylum if they request it after entering the country illegally, rather than at a legal port of entry.

He said his administration is finalizing an executive order for "sometime next week" about the asylum changes, though he didn't offer details.

The Immigration and Nationality Act currently requires the US government to allow immigrants to make asylum requests no matter how they crossed the border, and it's unclear what actions Trump could take to change that.

"Under this plan, the illegal aliens will no longer get a free pass into this country," Trump said. "Instead, migrants seeking asylum will have to present themselves lawfully at a port of entry."

Critics immediately seized on the vagueness of Trump's announcement, accusing him of stoking anti-immigrant sentiments ahead of the midterm elections next week and misrepresenting the asylum system.

What is Mexico doing?

The Mexican government has dramatically slowed the caravan's pace in recent days, blocking the migrants' efforts to arrange mass transportation to Mexico City via buses.

Mexican authorities have also "nibbled" at the edges of the caravan, according to the Associated Press, detaining 153 migrants in the second caravan during highway inspections. Authorities have also slowed some in the main caravan down by forcing migrants off freight trucks or overloaded pickup trucks

Though the government also deployed hundreds of federal police officers to Mexico's border with Guatemala, the caravans have pressed forward regardless.

What happens if it reaches the US border?

This is still unclear because details like their exact destination, pace, and numbers are still up in the air.

Part of the confusion also stems from a lack of clarity around how the migrants intend to cross the border. There are a few options for them, and each presents its own set of challenges:

• The migrants could choose to cross illegally and remain undetected, though a large group of migrants would be hard for Border Patrol agents to miss.
• They could follow the example of the caravan last spring, whose members legally presented themselves at a port of entry and requested asylum. This may present problems for those migrants who fled Central American countries for reasons like poverty and lack of job opportunities; under US law, those are not valid reasons to base an asylum claim on.
• They could try a mix of both tactics, crossing the border illegally, but immediately requesting asylum from US authorities once they're caught. They are legally entitled to make an asylum claim no matter how they cross the border, but Trump said Thursday he intended to bar migrants from requesting asylum if they cross illegally.

Another unknown is what role the military will eventually play if the caravan reaches the US border. Troops are forbidden under the Posse Comitatus Act from enforcing domestic law, and therefore cannot directly detain or deport immigrants.

Instead, the troops are expected to play a support role for Border Patrol agents, though the amount of support they'll need may depend on how many migrants actually reach the border.