DEARBORN, United States - US Republican officials and lawmakers have long warned of militants infiltrating the US through Mexico.

Arguing for stronger border security and a tougher stance on illegal immigration, they fear the Islamic State (IS) group might send militants into the United States through its southern border.

While those concerns have largely been dismissed by political rivals and the media, last month Secretary of Homeland Security Jeh Johnson told a US Senate panel that his department has set up a working group to crackdown on Middle Eastern migrants crossing the southern border illegally.

The Department of Homeland Security (DHS) is in charge of the US Customs and Border Protection (CBP), the agency in charge of securing the border. However, figures on the number of people of Middle Eastern descent entering the US illegally from Mexico remain unknown. The DHS also did not respond to MEE requests for comment.

Earlier in September, Johnson also told Fox News that he ordered CBP officials to increase scrutiny on people from “from other parts of the globe” as a counter-terrorism measure.

“We’re seeing illegal migrants coming from Africa, coming from the Middle East,” Johnson told Fox News. “And we’re doubling down on preventing that from happening before they even reach the southwest border.”

However, experts and advocates interviewed by Middle East Eye objected to Johnson’s statement, playing down the alleged threat and saying that targeting Middle Eastern migrants could be discriminatory.

The threat

The supposed danger of IS militants entering the US through Mexico was first brought to the national stage in 2014 by Republican senator and presidential candidate Ted Cruz.

“First and foremost, Washington should resolve to make border security a top priority finally, rather than an afterthought, of this plan in light of concerns about potential ISIS activities on our southern border, cited in a Texas Department of Public Safety bulletin reported by Fox News,” Cruz wrote in an op-ed published by CNN.

He added that the government is making it “far too easy” for terrorists to infiltrate the United States because of what he describes as lack of border security.

Other Republicans, including officials in Donald Trump’s campaign, have voiced similar fears. Trump is proposing building a wall along the southern border.

But fact-checking website PolitiFact concluded that “there’s no evidence that terrorists linked to ISIS have crossed the border, and many public safety officials have said flatly that it hasn’t happened”.

Engy Abdelkader, a Georgetown University professor who teaches courses on international terrorism, human rights and national security, said an influx of Central American unaccompanied minors at the border that coincided with attacks in Paris and San Bernardino last year renewed anxieties about would-be militants exploiting border vulnerabilities.

“There doesn't appear to be evidence of this happening in that particular context,” she told MEE in an email. “Still, it was around this time that now GOP presidential candidate Donald Trump announced his now infamous ban on Muslim immigration.”

Abdelkader cited legislation passed earlier this year by the Republican-controlled US House of Representatives, which directs DHS to conduct an assessment on potential militants and criminals seeking to enter the United States illegally through the southwest border.

The bill calls for “efforts to detect and prevent terrorists and instruments of terrorism from entering the United States”.

Abdelkader said Republican rhetoric on the bill, which refers to Syrian individuals and families found with fake passports in Central American countries, focuses on refugees.

"It is a very questionable act by the government." Abed Ayoub, legal director of ADC

"Significantly, these folks weren't tied to terrorism but like many other refugees, particularly those who are Muslim, are conflated with a terror threat," the professor added.

Republican officials argue that IS operatives could pose as refugees. Abdelkader said while that is a possibility, there is no concrete evidence demonstrating refugee-related militant infiltration happening in a large pattern in the United States or Europe.

Abdelkader pointed to other security threats in the United States.

"It's always possible that our morning commuter train might derail or a white supremacist might shoot up parishioners in a black church," she said.

Profiling

Abed Ayoub, the legal director of the American-Arab Anti-Discrimination Committee (ADC), a Washington-based rights group, accused DHS chief Johnson of advocating racial profiling.

Ayoub added that the Obama administration already has human rights issues with detaining migrants, including children, trying to cross the southern border.

He said the DHS group to intercept Middle Eastern migrants is legally problematic.

“It is a very questionable act by the government,” he told MEE. “You have to look at logistics. So anytime they see somebody crossing, whether they are a US citizen or not, are they going to be pulled over and questioned simply because they look Arab? Will there be extra questions asked to Middle Eastern individuals?”

Ayoub said the concern about human trafficking is valid, but it should not be addressed within the context of national security.

He added that ADC is aware of “individual cases” of Syrian refugees going to the US-Mexican border and claiming asylum, which is not illegal.

“The human trafficking component, there are ways to address that without racial profiling,” Ayoub continued. “If there is an issue with human trafficking involving the Arab community, then the government should reach out to Arab American groups like ADC to discuss what we can do given our resources within the community.”

He said there are no “affirmative numbers” on cases of Middle Eastern asylum seekers at the border or Arab migrants crossing into the United States illegally.

“All this does is further solidify that Arabs and Muslims are synonymous with terrorism.” -Dawud Walid, director of CAIR-Michigan

Dawud Walid, executive director of the Council on American Islamic Relations (CAIR) in Michigan, said fear of Middle Eastern migrants crossing the southern border illegally is not based on real evidence.

“For the past few years, the Department of Homeland Security has been operating from a framework that doesn’t even jibe with empirical data,” he said. “Keeping borders secure is fine, but a special working group specifically to stop people from the Middle East from coming in is quite bizarre.”

Walid added that since the 9/11 attacks, the majority of terror plots on US soil have not been carried by assailants from the Middle East.

“The small percentage of Arabs who have been involved in terrorist attacks, none of them were smuggled from Mexico. It doesn’t really make sense,” he said.

He added that the DHS group that Johnson referred to is a distraction to give the illusion that the federal government is making America safer.

“All this does is further solidify that Arabs and Muslims are synonymous with terrorism,” Walid said. “I am not sure if Homeland Security has any working groups for African or Chinese people being smuggled into America. There’s a specific focus on people coming from the Middle East. It’s troubling.”