(CNN) -- The number of migrants arriving at the US-Mexico border skyrocketed last year as Customs and Border Protection apprehended and deemed inadmissible nearly one million people during the government's 2019 fiscal year, according to acting Customs and Border Protection chief Mark Morgan.
That is 88% higher than the previous fiscal year, Morgan told reporters at the White House on Tuesday, adding that "these numbers are numbers that no immigration system is the world is designed to handle, including ours."
The number of families arriving at the border more than tripled any previous year on record, Morgan said. He pointed out, though, that the "apprehension and inadmissible" numbers have dropped in recent months, calling it an "unprecedented achievement."
There were just over 52,000 law enforcement actions on the southern border in September, down almost 65% from the May peak. Law enforcement actions generally include US Border Patrol arrests, as well as people deemed inadmissible at the legal ports of entry.
Morgan credited the Migrant Protection Protocols program, informally known as "remain in Mexico," coordination and efforts of Mexico and regional partnerships for the drop. He went out of his way to praise the efforts of Mexico, saying it "is something really for the history books."
Morgan also said Tuesday that CBP is "instituting that asylum IFR [Interim Final Rule] this week."
The rule, from the Departments of Justice and Homeland Security, prohibits migrants who have resided in or traveled through third countries from seeking asylum in the US, therefore barring people traveling through Mexico from being able to claim asylum.
Last month, the Supreme Court cleared the way for the Trump administration's rule that dramatically limits the ability of Central American migrants to claim asylum to go into effect nationwide while the appeals process plays out.
Morgan also touted the 71 miles of wall that have been built since Trump took office but acknowledged that the wall has not expanded to land where there was no wall before -- it continues to be replacement wall.
"Right now those 71 miles have not been new linear miles," he said, but added that CBP is getting ready to build new linear miles in the Rio Grande Valley. CBP expects, he said, to have installed approximately 450 miles of wall by the end of fiscal year 2020.
When asked how Mexico would be paying for the wall, Morgan said: "That's a political thing to me, to me, I don't care who pays for the wall, all I care about is that it's being built.
"By the end of 2020 we're going to have 450 miles of beautiful new wall," he said.
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