WASHINGTON — The Trump administration is drafting an executive action that would make it exceedingly difficult for Central Americans seeking asylum to gain entry at the U.S.-Mexico border, according to three sources familiar with the proposed measures.

The exact details have not yet been finalized, the sources said, and some of the more extreme ideas are a source of internal debate within the administration.

They have been drafted as President Donald Trump and his national security adviser, John Bolton, have grown increasingly frustrated with the number of migrants arriving at the southern border and the Honduran migrant caravan currently making its way to the U.S.

The details are expected to be finalized by early next week, the three sources said, with plans for the proposals to be unveiled by Trump in a speech on immigration.

The proposed executive action was first reported by The San Francisco Chronicle.

A White House official said: "The administration is considering a wide range of administrative, legal and legislative options to address the Democrat-created crisis of mass illegal immigration. No decisions have been made at this time. Nor will we forecast to smugglers or caravans what precise strategies will be employed."

One piece of the action under consideration would use an authority similar to that invoked by the travel ban, which would block entry to unauthorized immigrants who are not yet in the U.S., said the three sources. However, if these immigrants cross the U.S.-Mexico border and claim asylum, they would have the ability to apply for asylum.

To work around this, one senior administration official said the White House is also considering invoking a piece of the Immigration and Nationality Act where immigrants are required to wait in a contiguous territory, in this case Mexico, while their asylum case plays out.

Other, more extreme measures under consideration include not allowing those apprehended between ports of entry to claim asylum, said the senior administration official.

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To counter the Honduran migrant caravan now headed for the U.S., the official said the administration is also "examining plans" to temporarily close ports of entry at the southern border. But that plan has received pushback within the White House where officials have argued it would hurt interstate commerce, according to the official.

"This is going to impact a large range of people coming through who may or may not be part of the caravan, other people who are seeking asylum, or other forms of visas," said Marielena Hincapie, executive director of the National Immigration Law Center. "A lot of people are simply coming over to do business."

Two sources familiar with the plans expect a lawsuit to be filed to enjoin the executive action, but said the administration is still working to speed up the regulatory process to introduce an "interim final rule" that would be pushed without delay for public comment.

"We are pursuing all options," said the senior administration official. "The only problem is that it's an uncoordinated mess. We don't know what the caravan will do, which makes it hard to know what we will do."

On Thursday, Homeland Security Secretary Kirstjen Nielsen appeared to confirm reports that the Trump administration was considering sending 800 active-duty troops to the border. She told Fox News there was no "intention right now to shoot at people" from the caravan if they crossed the border.