(by Justin Fishel and Mike Levine, ABC News) – Top U.S. counterterrorism officials say they worry a potential terrorist could be hiding among refugees who are looking to come to the United States after escaping the brutal war in Syria.

“It’s clearly a population of concern,” the director of the National Counterterrorism Center*, Nicholas Rasmussen, told the House Homeland Security Committee on February 11.  [*The National Counterterrorism Center (NCTC) is a government organization responsible for national and international counterterrorism efforts. Part of the Office of the Director of National Intelligence, the group brings together specialists from other federal agencies, including the CIA, the FBI, and the Department of Defense. The center analyzes terrorism intelligence including potential domestic threat intelligence; monitors communications internationally and domestically for potential threats; generates actionable information to potentially prevent criminal acts domestically; stores terrorism information; supports U.S. counterterrorism activities using information technology (IT); and plans counter-terrorism activities as directed by the President, the National Security Council, and the Homeland Security Council.]

Homeland Security Committee Chairman Mike McCaul, R-Texas, went further, saying it would be a “huge mistake” to bring refugees from the conflict to the U.S. – even as an estimated 4 million men, women and children have been forced to flee Syria and another 7 million have been displaced from their homes there, unable to leave.

[In a letter sent to the White House, Chairman McCaul, and Congressmen Peter King and Candice Miller, who chair subcommittees, said the administration’s plan “raises serious national security concerns.”

The letter, dated Jan. 28, said the United States lacks the resources to fully investigate the backgrounds of refugees from Syria, a base for Islamic State militants, before they are admitted to the U.S.]

Senior officials leading the State Department’s refugee efforts say the U.S. government has a long history of caring for the innocent victims of war.

“It’s not a matter of should we do it, it’s really a matter of how we do it,” Larry Bartlett, the State Department’s director of Refugee Admission for the Bureau of Population, Refugees and Migration, told ABC News. “One of the fundamental principles of our country is that we care about others. We will help others.”

Bartlett insisted every refugee is vetted through an “intensive” system, drawing on information and expertise from several U.S. intelligence agencies, including the Defense Department.

“We have a very slow process of moving refugees through our pipeline, and part of it is because of the security vetting component,” Bartlett said.

Homeland Security officials also testified Wednesday, Feb. 11 that any potential refugees from Syria would receive “the most rigorous screening.”

“Any tasking we’re given … will be as thorough as we can make it,” said Francis Taylor, the head of the Department of Homeland Security’s intelligence office.

Yet that’s not reassurance enough for McCaul and other leading Republicans, who recently penned a letter to National Security Advisor Susan Rice cautioning that the U.S. government’s ability to screen refugees from Syria might not be sufficient.

“The continued civil war and destabilization in Syria undeniably make it more difficult to acquire the information needed to conduct reliable threat assessments on specific refugees,” they wrote in the letter two weeks ago.

With tens of thousands of Syrians joining groups in the region like the Islamic State, the U.S. government “cannot allow the refugee process to become a backdoor for jihadists,” they added.

At the hearing Wednesday, an FBI official also questioned whether the U.S. intelligence community – with few assets on the ground in Syria and little insight into the country from elsewhere – can provide authorities with the information they need to properly determine whether any refugee could pose a threat.

“You have to have information to vet,” said FBI Assistant Director Michael Steinbach, who heads the bureau’s counterterrorism division. “Databases don’t [have] the information on those individuals, and that’s the concern.”

Still, Rasmussen vowed “the full weight of the U.S. intelligence community” would be employed to “unearth” any concerning information about potential refugees. And Bartlett and other State Department officials say the U.S. is far from opening the flood gates.

Of the 7 million of Syrians seeking refuge, only about 500 have been let in the United States. Compare that with Syria’s neighbor, Jordan, whose Foreign Minister recently said they’ve let in over 80,000 Syrians — a figure that represents nearly 21 percent of Jordan’s total population. Or compare it to the response to the Iraq war, with the U.S. admitting over 120,000 Iraqis.

So far Germany and Sweden are leading the charge when it comes to accepting Syrians. Germany has let in nearly 12,000 refugees, not including those who have sought asylum there.

Officials at the State Department were quick to report that:

overall the U.S. accepts more refugees than the rest of the world combined.

Bartlett and others also say they expect the U.S. to steadily increase the number of Syrians it accepts as applications at the United Nations continue to pile up.

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