In addition, so far in 2015, more than 10 people have attempted terrorist attacks inside the United States “after being inspired by or directed by foreign terrorists,” Carlin said.

From that grim statistic, administration officials take comfort in the notion that their measures to block travel are working.

“As it’s become more difficult for these individuals to travel overseas to join the foreign terrorist fight, ISIL will issue direction for them to attempt attacks here at home,” Carlin said, using the administration’s preferred acronym for the group.

“ISIL has lost a huge chunk of territory in northern Syria and significantly is now cut off from all but 68 miles of a nearly 600-mile border between Syria and Turkey,” said Deputy Secretary of State Anthony Blinken.