Republican Florida Republican Gov. Gov. Ron DeSantis claimed during the Nov. 8 Republican debate that terrorists have crossed the southern border.

“We are not going to send our sons and daughters to Ukraine. I am going to send troops to our southern border. If you look at the threats that we face, terrorists have crossed the southern border.” DeSantis said.

Check Your Fact looked more into this claim. Immigration and Customs Enforcement (ICE) recently announced it arrested a non-citizen that crossed the U.S.-Mexico border that was wanted for “terroristic activities” in Senegal.

“On Oct. 17, Enforcement and Removal Operations (ERO) New York City announced the arrest of an unlawfully present Mauritanian or Senegalese citizen wanted by Senegalese authorities for criminal conspiracy in relation to a terrorist organization; destruction, degradation and damages in relation to a terrorist organization; acts or preparatory acts aimed at compromising public safety or causing serious political troubles; direct provocation of an armed crowd; and holding arms without prior administrative authorization,” reads the press release.

A DeSantis campaign spokesperson pointed to the recent ICE arrest, a Fox News article about a Columbian migrant that crossed into the U.S. illegally before being arrested for being on the TSDS in May 2022 and a June 2023 tweet from Fox News national correspondent Bill Melugin about “CBP reports there have now been 125 people on the FBI’s terror watchlist arrested by Border Patrol agents at the southern border.”

“Note that these 125 were only those who were apprehended at the border and don’t include individuals who got away. DHS Secretary Alejandro Mayorkas has testified under oath there were over 600,000 known gotaways at the border in Fiscal Year 2023,” the spokesperson said. (RELATED: X Post Makes False Claim About UN, Trucks Entering Gaza Strip)

A 2023 Department of Homeland Security Office of the Inspector General (OIG) report described the Columbian migrant as a “suspected terrorist.”

“Our objective was to review CBP’s screening of a suspected terrorist and ICE’s subsequent arrest of the suspected terrorist released into the United States,” the OIG report reads.

A Customs and Border Patrol (CBP) spokesperson directed Check Your Fact to the agency’s 2023 statistics, where it reported that they have had 169 encounters with individuals on the Terrorist Screening Dataset in FY 2023 on the southwestern border between ports of entry. 

“The Terrorist Screening Dataset (TSDS) – also known as the ‘watchlist’ – is the U.S. government’s database that contains sensitive information on terrorist identities. The TSDS originated as the consolidated terrorist watchlist to house information on known or suspected terrorists (KSTs) but has evolved over the last decade to include additional individuals who represent a potential threat to the United States, including known affiliates of watchlisted individuals,” reads the CBP website.

Alex Nowrasteh, the vice president for economic and social policy studies at the Cato Institute, a libertarian think tank, told Check Your Fact in an email that “[h]its on the TSDB aren’t very meaningful.”

“Hits on the TSDB aren’t very meaningful. The TSDB included many non-terrorists and members of groups that pose no threat to the U.S., like FARC. Not a single one of those people apprehended who showed up on the TSDB has been prosecuted for a terrorism offense, far as I can tell,” Nowrasteh said to Check Your Fact.

A DHS official told Check Your Fact “encounters of known or suspected terrorists attempting to cross the Southern Border, or encounters of those associated with such individuals, are uncommon.”

“These encounters may include individuals who are not known or suspected terrorists, but can include individuals associated with a known or suspected terrorist, to include family members of watch listed individuals,” the official said.

The official and the CBP spokesperson directed Check Your Fact to the FBI about TSDS encounters. A FBI spokesperson said the bureau had no comment.

Ian Mitch, a senior policy researcher and terrorism expert at RAND, told Check Your Fact that “it is true that individuals on terrorism watchlists have attempted to enter the country” at the U.S.-Mexico border.

“It is true that individuals on terrorism watchlists have attempted to enter the country between ports of entry at the SW border. And the number of such individuals has been on the rise in the last two years,” Mitch said. But Mitch cautioned about the numbers and what they meant.

“That’s concerning, for sure. But, it’s important to note that there are likely many thousands of people on terrorism watchlists. And, as CBP notes… these individuals included both ‘known or suspected terrorist’ and affiliates of watch listed individuals, such as friends and families. So it should not be assumed that these individuals are traveling for terrorism purposes. In fact, it’s likely that most, if not all, are merely economic migrants or individuals seeking humanitarian protections,” Mitch said.

The New York Times rated DeSantis’ claim as false, writing,”Since 1975, no one has been killed or injured in a terrorist attack in the United States that involved someone who came across the border illegally” and citing Nowrasteh.

But Nowrasteh’s research does not show that no terrorists have ever crossed the border. Check Your Fact asked Nowrasteh about terrorists crossing the border since 1975 and he pointed to his Sept. 18 written congressional testimony.

Nowrasteh wrote that “nine foreign‐​born terrorists entered the United States illegally during the 1975–2022 period. Three of the nine convicted illegal immigrant terrorists entered illegally by crossing the U.S.-Mexico border.” The three, all brothers, came into the country illegally when they were young children at the ages of 1,3 and 5.

“The Duka brothers were ‘got aways,’ which is defined as an unlawful border crosser who (1) is directly or indirectly observed making an unlawful entry into the United States; (2) is not apprehended; and (3) is not a turn back,” Nowrasteh wrote. He also cited the case of Abdulahi Hasan Sharif.

“Abdulahi Hasan Sharif is the closest example of a possible asylum seeker or illegal immigrant having crossed the U.S.-Mexico border and then committing an attack. He entered along the U.S.-Mexico border in 2011 and was immediately apprehended by Border Patrol. He may have possibly applied for asylum, but an immigration judge ordered him to be removed and Sharif never appealed that decision. Instead, he went to Canada and wounded five people years later in a vehicle attack in Edmonton in 2017,” Nowrasteh wrote.

Sharif was convicted on 11 charges, including five counts of attempted murder, after he rammed a car into a police officer and stabbed him, before leading police on a high speed chase and hitting four pedestrians, according to Edmonton Journal. He was not charged nor convicted of any terrorism-related charges, though a flag of the Islamic State of Iraq and Syria (ISIS) was found in his car, the outlet reported.

The Royal Canadian Mounted Police (RCMP) said that they believe Sharif’s actions were a terrorist attack, according to CBC News. Superintendent Stacey Talbot said that officials did not pursue terrorism charges because the other charges were deemed to have a better chance of conviction, the outlet reported.

Nowrasteh told Check Your Fact in an email that the Sharif’s attack was “not a terrorist attack in the United States.”

“I’d rank [DeSantis’] claim as ‘untrue’ in the context of the question and debate which was about US terrorism,” Nowrasteh said. He also said to Check Your Fact that “I want to be clear: There is a chance that terrorists could cross the border and commit an attack, it just hasn’t happened and we shouldn’t expect much activity on that front.”

Andrew Arthur, a fellow with the Center for Immigration Studies, a think tank that advocates for lower immigration, told Check Your Fact that the New York Times fact-check was a “non-sequitur.”

“I’m a little surprised that the NYT ran that response, which is a non-sequitur. There is a big difference between DeSantis’ claim that ‘If you look at the threats that we face, terrorists have come in through our southern border’ and Alex Nowastreh’s assertion that ‘Since 1975, no one has been killed or injured in a terrorist attack in the United States that involved someone who came across the border illegally,” Arthur said.

“We know that a terrorist has come across the border because ICE disclosed that fact in an October 19 press release captioned ‘ERO New York City arrests noncitizen wanted in Senegal for terroristic activities,'” Arthur added.

There have also been past cases of members of terrorist organizations and individuals who sympathize with groups designated as terrorist organizations crossing and attempting to cross the southern border. (RELATED: Fact-Checking The Third Republican Presidential Primary Debate)

Four members of the Tamil Tigers, a Sri Lankan rebel group designated as a foreign terrorist organization by the U.S., attempted to cross the U.S.-Mexico border after the September 11 attacks, though were caught, according to a 2005 Associated Press (AP) report. Mahmoud Youssef Kourani, a Lebanese illegal immigrant who crossed from Mexico, was convicted in 2005 of conspiring to support Hezbollah, which the U.S. has designated as a terrorist organization, the AP reported at the time.

A 2004 report, titled “9/11 and Terroristic Travel,” found that at least one smuggler was arrested and convicted of smuggling Lebanese nationals sympathetic to Hamas and Hezbollah.

“One smuggler, Salim Boughader-Mucharrafille, smuggled Lebanese nationals sympathetic to Hamas and Hizbollah into the United States and relied on corrupt Mexican officials in Beirut, Mexico City and Tijuana to facilitate their travel. Specifically, Boughader obtained Mexican tourist visas from an official at the Mexican embassy in Beirut to facilitate the travel of humans to Mexico,” the report reads.

The Daily Caller News Foundation reported Jan. 29 that a”a confirmed member of al-Shabaab” did cross the US-Mexico border illegally in March 2023, citing a memo the outlet obtained. The member was later arrested in January 2024 by ICE. Al-Shabaab has been designated a foreign terrorist organization since 2008 by the State Department.

This reporting was later confirmed CE Acting Director Patrick Lechleitner during a Feb. 1 press briefing.

““I can say that for this individual, within 20 – within 48 hours, excuse me – of ICE becoming aware of his status as on the watch list, within 48 hours, he was apprehended. I want to commend our personnel because as soon as we became aware of that, within 48 hours, he was apprehended and he’s currently in ICE custody,” Lechleitner said.

Check Your Fact reached out to the New York Times for comment.

Update 1/29/2024: This article has been updated with a report from the Daily Caller News Foundation that states a member of Al-Shabaab, which is designated as a terrorist organization by the State Department, crossed the border illegally in March 2023. This member was arrested in January 2024 by ICE.

Update 2/1/2024: This article has been updated to note that ICE’s acting director confirmed the Daily Caller News Foundation’s reporting.