House Democrats, who shrugged off the idea of terrorists crossing the border illegally, have remained silent over the arrest of two Yemeni men on a terror watchlist at the southern border.

The U.S. Customs and Border Protection (CBP) on Monday said a Yemeni man, who was apprehended at the border by Border Patrol agents, was among those included in the FBI's Terrorism Watch List.

The individual, who was arrested on March 30, was the second Yemini national whose name was on the Terrorism Watch List in two months. The first Yemini man was arrested on Jan. 29. Both of the apprehended suspects were on the no-fly list in addition to the terror list, Fox News reported.

Last month, House Minority Leader Kevin McCarthy issued a warning regarding the possibility of individuals included on the watch list from Middle Eastern countries who use or take advantage of the border crisis to get across the border. However, some House Democrats shrugged off the idea and downplayed the warning.

READ NEXT: 11 Iranian Migrants Caught Illegally Crossing the U.S.-Mexico Border

Democrats on Possible Terrorists at the Border

"When you go out to Monument 3 and you talk to those agents, it's not just people from Mexico or Honduras or El Salvador," McCarthy said.

McCarthy noted that border agents are also finding people from Yemen, Iran, and Turkey. He added that "people on the terrorist watch list they are catching and they are rushing it all at once."

In denouncing McCarthy's warning, Representative Ruben Gallego called the allegation of McCarthy weird because the chairman of the subcommittee on Intelligence and Special Operations did not hear anything about the issue. 

Gallego also tweeted that McCarthy could either be wrong or lying. Gallego also asked McCarthy for a "classified briefing" so that members can see where the information was derived.

Representative Veronica Escobar, a Democrat from Texas, accused McCarthy of trying to "fuel the division" and make people afraid of immigrants.

2 Yemeni Men Arrested

According to Reuters, the two Yemeni men were apprehended near the Calexico Port of Entry in California by Border Patrol agents.

The men, ages 33 and 26, were transported to El Centro Processing Center for Immigration, where they have undergone a criminal screening.

CBP data showed that border crossings hit a 15-year-high last month as authorities caught more than 171,000 migrants at the southern border.

Of the 171,000 migrants, 19,000 were believed to be unaccompanied minors, 53,000 were family members traveling together, and 99,000 were single adults.

With the surge of unaccompanied migrant children arriving at the southern border, the Biden administration is scrambling to find space in shelters for them.

The Biden administration has been blamed for the flood of Mexican and Central American illegal migrants at the southern border that reportedly stemmed from his undoing of former President Donald Trump's border policies.

Meanwhile, Chief Patrol Agent Gregory Bovino said in a statement that protecting the country from terrorists is part of the Border Patrol's mission.

READ MORE: Biden Under Investigation by GAO for Border Wall Funds Freeze

WATCH: Yemeni Nationals On Terror Watch List Arrested At California-Mexico Border - From CBS Los Angeles