UPDATE 3-Obama urges Americans remain vigilant against homegrown threats
(Adds Obama quotes, paragraphs 4, 8, poll figures paragraph 9, other details)
By Roberta Rampton and Ayesha Rascoe
WASHINGTON Dec 18 (Reuters) - President Barack Obama urged Americans to remain vigilant against the potential threat of homegrown Islamic State militants on Friday, acknowledging the difficulty of tracking "lone wolf" attackers like those who went on a shooting spree in California.
Obama appeared in the White House press briefing room for a year-end news conference shortly before traveling to San Bernardino, California, where the Dec. 2 shootings took place, to meet privately with families of the victims en route to spending the holidays in Hawaii.
Obama talked tough about the prospects of defeating Islamic State militants who control broad swathes of territory in Syria and Iraq but admitted U.S. law enforcement agencies have limitations in tracking the threat at home.
"It's not that different from us trying to detect the next mass shooter. You don't always see it. They're not always communicating publicly," Obama said.
A day after telling Americans that there is no current credible militant threat in the United States, Obama said that "lone wolf plotters" are difficult to track, particularly if they are a husband and wife like the two radicalized Muslims who killed 14 people in San Bernardino.
As for U.S. efforts to track potential attackers, Obama said social media postings by potential militant suspects are constantly being reviewed by law enforcement agencies but that private online communications are far more difficult to track.
He said he believes law enforcement officials have struck the right balance between privacy concerns and making sure information gathering is carried out. Continuación...