"At this stage we do not yet know why this terrible event occurred," Obama said, speaking from the Oval Office, while raising the possibility that the shooting could also have been the result of workplace violence.
"It is possible that this was terrorist related, but we don't know. It's also possible that this was was workplace related," Obama said, adding that more conclusions will be drawn after the FBI conducts a large number of interviews.
On Wednesday, 14 people were killed in a shooting rampage at the Inland Regional Center, marking the deadliest shooting in the U.S. since more than two dozen, mostly children, were killed in Newtown, Connecticut
, about three years ago.
"Our first order of business is to send our thoughts and prayers to those who have been killed," Obama said.
Obama also said the FBI is taking the lead on investigating the shooting.
The President, who spoke to reporters following a national security briefing, was joined in the Oval Office by Vice President Joe Biden, Attorney General Loretta Lynch, FBI Director James Comey, Director of National Intelligence James Clapper, National Security Adviser Susan Rice and other top officials.
Earlier on Thursday, Lynch condemned the massacre saying, "Violence like this has no place in this country. This is not what we stand for, this is not what we do."
Lynch, who was participating in a White House and Justice Department discussing incarceration and poverty, opened her remarks saying that the investigation into the shooting in San Bernardino is in its early stages adding, "We don't know a lot right now."
"But one thing is clear, that violence like this has no place in this country and in this nation," Lynch said, speaking at the previously scheduled White House event on criminal justice. "This is not what we stand for, this is not what we do, this is not what we work for. This is not what we live for, it's antithetical to our values."
Senior White House adviser Valerie Jarrett also spoke about San Bernardino at the White House event, calling for a moment of silence for victims and their families.
Lynch said the local authorities on the scene will be providing additional information as the investigation unfolds.
After her remarks on San Bernardino, the attorney general discussed incarceration and poverty which she said are of "equal seriousness" to mass shootings.