Sen. Josh Hawley, R-Mo., said the way to stop the crisis at the southern border with Mexico is by expanding the Remain in Mexico Program and holding Mexico’s “feet to the fire.”

The Remain in Mexico Program -- also known as the Migrant Protection Protocols -- institutes a policy that outlines procedures under which the U.S. government will return certain asylum seekers to Mexico to wait through the duration of their cases pending in the U.S. immigration court system.

Appearing on “America’s Newsroom” on Monday, Hawley told hosts Bill Hemmer and Sandra Smith that the Remain in Mexico Program would help end catch-and-release in the United States and give immigration officers the ability to return illegal immigrants to Mexico while their asylum claims are processed.

“Getting Mexico to commit to actually policing its southern border in a more serious fashion is absolutely necessary,” said Hawley. “We need to create Mexico as a ‘Safe Third Country,’ as it’s called, where all of these claims hopefully can be processed in Mexico before these folks come to our southern border.”

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Making Mexico a “Safe Third Country” would mean asylum-seekers who pass through the country to claim refuge in the United States would have a harder time doing so. The idea, which Mexico has long opposed, was discussed during recent negotiations. However, Mexican Foreign Minister Marcelo Ebrard has said his country did not agree to it, even as Mexican diplomats said talks would continue.

“Listen, it’s important to hold Mexico’s feet to the fire,” urged Hawley. “We need Mexico as a full and equal partner here. Something that the Mexican ambassador said to me is, ‘Well, we just can’t have Mexico, we just can’t have this many migrants in our country.’ I said, ‘Think about what it’s like for our country.’”

Fox News has learned more than 200,000 migrants claiming to be part of families have been released into the U.S. since the end of December 2018 and United States Customs and Border Patrol reported that 144,278 individuals have been apprehended or deemed inadmissible along the southwest border since in the month of May.

On “Fox News Sunday,” acting Department of Homeland Security Secretary Kevin McAleenan said he agreed with a CBP official who said the border was “bursting at the seams.”

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President Trump had threatened a five percent tariff on Mexican goods to take effect unless Mexico did more to address the humanitarian crisis. On Friday the president purportedly struck a deal with Mexico, but on Sunday he bluntly suggested he might again seek to impose punishing tariffs on Mexico if its cooperation falls short in the future.

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According to the joint declaration issued by the State Department, Mexico will take “unprecedented steps to increase enforcement to curb irregular migration, to include the deployment of its National Guard throughout Mexico, giving priority to its southern border.”