Alan Gomez | USA TODAY

AP

Susan Walsh, AP

More than 600,000 foreign travelers who legally entered the United States in 2017 overstayed their visas and remained in the country by the end of the year, according to Department of Homeland Security data released Tuesday.

That figure represents only 1.15 percent of the more than 52 million foreigners who legally entered the U.S. through air and seaports in 2017, and is down from 1.25 percent the year before. But it marked the second straight year that more than 600,000 visitors stayed past the expiration of their visa, turning them into undocumented immigrants at risk of deportation.

President Donald Trump has urged Congress to complete a biometric entry-exit tracking system that would better monitor foreigners who legally visit the United States. Completion of that system, which uses fingerprints and iris scans to more accurately capture when people enter and exit the country, was included in an executive order he signed shortly after being sworn in as president.

But Trump and his administration have focused far more on building a wall along the southern border with Mexico, even threatening a government shutdown in the fall if Congress doesn't give him a $5 billion down payment this year to continue expanding it.

Immigration experts say that shows the president has been misguided in his immigration enforcement strategy.

DHS data shows that illegal immigration across the southern border is at historic lows – slightly more than 300,000 immigrants were caught crossing the border in 2017. That's down from a high of 1.6 million in 2000, according to Border Patrol data.

In fact, more Mexicans are returning to their native country than coming to the United States, according to a 2015 report from the Pew Research Center. That reversal has led to a drop in the number of undocumented immigrants from Mexico living in the United States by more than 1 million, according to a 2017 report from Pew Research Center.

Ali Noorani, executive director of the National Immigration Forum, a group that advocates for immigrants, said Trump's obsession with a border wall in light of the visa overstay data shows that he's "not serious about a sound immigration policy." Noorani said the president should be focusing instead on improving port security and broader changes to the legal immigration system.

"Instead, the president wants to spend tens of billions of dollars on a border wall that doesn't solve any real problems, but makes for a chant at a rally," he said.

According to the DHS report, the department made some improvements in 2017 to ensure that foreigners left the country when they were required. It continued testing biometric screening processes at several air and seaports. And officials started emailing foreigners who were part of the Visa Waiver Program when the end of their visits were coming up. Citizens of 38 countries, mostly in Europe, are part of the program, which allows them to visit the U.S. for up to 90 days without first getting a visa.

Despite those gradual improvements, the report acknowledges that there is "no specific cause that can be directly attributed to the decrease in overstay rates" in 2017.

Other findings from the report: