Continuing a week-long push to underscore his command of national security dangers, Obama said he understood why unease has spread after attacks in France and California. But he sought to bolster the country's mettle ahead of a busy holiday travel season.
"If you target Americans, you will have no safe haven," he said at the suburban headquarters of his counterterrorism command center. "We will find you and we will defend our nation."
It's rare for Obama to visit the National Counterterrorism Center, housed in an unmarked building amid corporate headquarters in Tysons Corner, Virginia. Typically, Obama receives a briefing on Christmastime terror threats in the White House Situation Room.
But amid heightened fears of an attack on U.S. soil, prompted by the ISIS-inspired attack in San Bernardino, California
, Obama has made a public show of preparedness.
He visited the Pentagon Monday for an update on military progress against the terror group and has tasked the Department of Homeland Security with updating its system for communicating potential threats to the American people.
"When terrorists pull off a despicable act like what happened in San Bernardino, it tears at our hearts," Obama said Thursday, acknowledging that it was natural for Americans to feel anxious. "But it also stiffens our resolve. To learn whatever lessons we can and make any improvements that are needed."
U.S. officials have strengthened their focus on screening people entering the United States after signs of radicalization were missed when processing the fiancé visa for Tashfeen Malik
, one of the San Bernardino shooters
Officials are reviewing how those types of visas are granted and say a greater emphasis on analyzing social media could result.
Speaking Thursday, U.S. officials described an already-rigorous process that includes multiple screening stages and collecting of biometric data like fingerprints.
The review ordered by Obama will continue through the holiday season, the officials said, in an attempt to harden defenses against potential terrorists entering the country.
The holiday season has traditionally brought with it some sort of potential terrorist threats. Past failed attempts to bring down jetliners -- including the foiled shoe and underwear bomb plots -- occurred during the winter vacation period.
Busy tourist sites have increased security, including Walt Disney World in Florida, which is installing metal detectors
for entering guests.
Obama himself departs for a 16-day vacation in Hawaii on Friday, stopping on the way to visit privately with family members of those shot
in San Bernardino
earlier this month.