U.S. senators are urging the Trump administration to make an agreement with Mexico that would stop some of the 7,000 people traveling north from crossing the border.
Senate Judiciary Chairman Chuck Grassley and Sen. Mike Lee, both Republicans, say a "third-party" agreement would require those asking for asylum to do so in their first country of arrival.
Most of the caravan has come from Honduras and other Central American countries and are currently in Mexico. Many have said they are coming to the U.S. to seek a better life, which would not qualify them for asylum under U.S. laws.
In the letter to the Department of Homeland Security and the State Department on Tuesday, Grassley said asylum seekers arriving to the European Union must register their claims in the first country of arrival.
President Donald Trump is acknowledging there's "no proof" that Middle Easterners are mixed in with the Central American migrants moving in a caravan toward the U.S. southern border.
Asked for evidence of his claim during a bill signing Tuesday, Trump says, "There's no proof of anything." But he says "they could very well be" in the caravan.
Trump had claimed in a tweet Monday that "Criminals and unknown Middle Easterners" were mixed in with the migrants fleeing violence or poverty.
He told reporters Tuesday that the U.S. Border Patrol has "intercepted many people from the Middle East" over the course of the year.
Associated Press journalists who have traveled with the migrant caravan for more than a week have seen no evidence of Trump's claims.
Trump administration officials say they are still evaluating what to do if a migrant caravan arrives at the U.S. southern border. That's despite threats by the president to declare a national emergency or rescind aid from the countries whose people are journeying north.
President Donald Trump's Twitter feed reveals bits and pieces of potential outcomes being discussed regularly by top immigration officials and his close advisers in closed-door meetings.
Several administration officials told The Associated Press those meetings have gotten increasingly heated in the past week, including one that turned into a shouting match.
They spoke on condition of anonymity because they were not authorized to speak publicly on the topic.
The caravan comes on the heels of a surge in apprehensions of families at the border, rankling Trump.
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