Eight Syrian refugees turned themselves in to immigration authorities along the Texas-Mexico border this week, officials said Thursday. Their arrival and uncertainty about their future in the United States comes at a time of political upheaval over Syrian refugees following the deadly Paris attacks.

Two families -- two men, two women and four children -- presented themselves Tuesday at the port of entry of the South Texas city of Laredo, the Department of Homeland Security said in a release. The men were taken to a U.S. Immigration and Customs Enforcement detention center in Pearsall, and the women and children to one in Dilley.

One day earlier, five Pakistanis immigrants and one Afghan immigrant were caught near the Arizona border.

Republican Gov. Greg Abbott, who along with several other governors across the country recently urged President Barack Obama to suspend entrance for Syrian refugees following last week's deadly attacks in Paris, tweeted a link Wednesday night to the conservative Breitbart News Network website, which reported that Syrians had been "caught" at the border.

"THIS is why Texas is vigilant about Syrian refugees," the governor wrote.

THIS is why Texas is vigilant about Syrian refugees--> REPORT: 8 Syrians Caught at Texas Border in Laredo. #tcot https://t.co/trfqhGcNAu — Greg Abbott (@GregAbbott_TX) November 19, 2015

Abbott and House Republicans have expressed concerned over the possibility Syrian refugees could pose a security threat to the country. Abbott is one of more than two dozen governors seeking to ban Syrian refugees from their states in the wake of Friday's deadly terrorist attacks in Paris.

Republican presidential candidate Donald Trump followed suit Thursday with a tweet of his own: "ISIS, Maybe? I told you so. WE NEED A BIG & BEAUTIFUL WALL."

Eight Syrians were just caught on the southern border trying to get into the U.S. ISIS maybe? I told you so. WE NEED A BIG & BEAUTIFUL WALL! — Donald J. Trump (@realDonaldTrump) November 19, 2015

Hundreds of thousands of people have fled Syria to escape the civil war, most of them to Europe. For Syrians with means, a lengthy trek to the U.S. border could provide another path to asylum. Between 2004 and 2013, some 1,449 Syrians were granted asylum in the United States, most in 2012 and 2013, and were not part of the 70,000 refugees from around the world that the U.S. accepts annually.

The Obama administration announced earlier this year that the number of people invited to move to the U.S. as refugees would be increased to 85,000 in the coming year, including about 10,000 Syrians. That program is now under scrutiny, and the U.S. House overwhelmingly approved GOP-backed legislation on Thursday that puts up new hurdles for Syrian and Iraqi refugees trying to come to the U.S.

More than 145,000 people from countries other than Mexico were apprehended at the U.S.-Mexico border during the 2015 federal budget year that ended Sept. 30. The overwhelming majority was from Central America, though five were from Syria. Border Patrol agents apprehended 14 Syrians in federal fiscal year 2014.

The Syrians turned themselves over to authorities in Texas one day after the Border Patrol in Arizona caught five Pakistanis and an Afghan trying to sneak into the country. The six were apprehended along with two smugglers accompanying the group near the Arizona town of Sonoita.

The Border Patrol said in a statement that it "checked their identities against numerous law enforcement and national security related databases" and found no "derogatory information" about the individuals. They remain in federal custody.

However, the recent arrivals appear to stand a reasonable chance of staying in the country, at least for a little while. Immigrants from countries other than Mexico or Canada cannot be quickly repatriated and are often detained for at least a few days after crossing.

Plus, asylum seekers who pass the initial credible fear interview, the first step in the asylum process, are often released from custody to await a court hearing. Currently, a backlog of more than 450,000 cases is pending in federal immigration courts.