Speaking one day after at least 14 people died in a mass shooting in San Bernardino, Calif., President Obama said the investigation into the attack is now in the hands of the FBI — and warned that it may take some time to find answers.

Obama began his remarks from the Oval Office by noting that at this stage in the investigation, the two shooters' motivations are not known.

"At this stage, we do not yet know why this terrible event occurred," he said. "We do know that the two individuals who were killed were equipped with weapons and appeared to have access to additional weaponry at their homes."

The FBI will be cooperating and consulting with local law enforcement in the investigation, Obama said, and until interviews are conducted, relationships examined and social media records analyzed, authorities will not be able to answer questions about the attack — including whether it was an act of terrorism or was "workplace related."

"Rest assured that we will get to the bottom of this," he said.

Obama said he told the mayor of San Bernardino that "the entire country is thinking about that community," and said his deepest condolences are with victims and their families.

The president also reiterated his calls for changes to gun control laws in the U.S. While many Americans see the prevalence of mass shootings and feel that there's nothing an individual can do, he said, "we all have a part to play" when it comes to reducing gun violence.

Obama suggested America consider "basic steps" to make it more difficult to access weapons.

"As the investigation rolls forward, it's going to be important for all of us, including our legislatures, to see what we can do to make sure that when individuals decide that they want to do somebody harm, we're making it a little harder for them to do it," he said.

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