The Department of Homeland Security clarified rumors to Congress regarding the possibility of the Islamic State -- also known as ISIS and ISIL -- crossing the U.S.-Mexican border.

DHS Secretary Jeh Johnson at the Council on Foreign Relations this week said, "At present, we have no credible information that ISIL is planning to attack the homeland of the United States."

Despite no credible threats in the U.S., Johnson said it does not reduce ISIL's dangerous presence elsewhere.

Johnson said, "Though we know of no credible information that ISIL is planning to attack the homeland at present, we know that ISIL is prepared to kill innocent Americans they encounter because they are Americans -- in a public and depraved manner. We know ISIL views the United States as an enemy, and we know that ISIL's leaders have themselves said they will soon be in 'direct confrontation' with the United States."

Testimony from the DHS' Customs and Border Protection Office of Field Operations, CBP Office of Intelligence and Investigative Liaison and the I&A Office of Analysis examined the role of ISIS and border protection. The testimony, to the House Committee on Homeland Security, Subcommittee on Border and Maritime Security hearing titled "One Flight Away: Examination of the Threat posed by ISIS Terrorists with Western Passports," reaffirmed the CBP serves as the "frontline" defending U.S. borders against terrorists and instruments of terror while managing customs, immigration and agricultural protection.

The written testimony disclosed foreign fighters supporting ISIS have the ability to travel to their native country and beyond, and it could pose a threat to the U.S. The DHS, however, has been "continually refining" its risk-based strategy and collaborating with fellow federal security agencies.

"CBP has partnered with the Department of Defense's U.S. Special Operations Command to synchronize planning, authorities, and capabilities to enhance each organization's ability to rapidly and persistently address threats to the homeland before they reach our physical borders," the testimony disclosed.

DHS Undersecretary for Intelligence and Analysis Francis Taylor told members of Congress, including Sen. John McCain, R-Ariz., that social media exchanges, including Twitter, included discussion of entering the U.S. through the northern Mexican border. While noting "any infiltration" across the border would be a threat, Taylor said he's "satisfied" there's enough intelligence and capabilities to prevent such activities.

After DHS stated there's no credible ISIS threat within the U.S. and the border is secured from terrorists, McCain told CNN, "There is Twitter traffic right now and Facebook traffic, where they are urging attacks on the United States of America. And there is a great concern that our southern border and our northern border is porous and that they will be coming across."

But, DHS' Intelligence and Analysis Office's senior official Jennifer Lasley also told the House Committee on Homeland Security, "We don't have any credible information, that we are aware of, of known or suspected terrorists coming across the border."