Police carry out a manhunt after Wednesday's mass shooting in San Bernardino, California. Attackers opened fire on a holiday party at a social services agency, killing 14 people and wounding 17 others, before fleeing the scene. MIKE BLAKE/REUTERS

Obama says California mass shooting possibly terror-related or workplace-related

WASHINGTON - US President Barack Obama said on Thursday the motives of shooters who killed 14 people at a Southern California social services center on Wednesday remained unclear, adding that the incident could be terror-related or workplace-related.

"At this stage, we do not yet know why the terrible event occurred," Obama told reporters after meeting his national security advisers at the White House.

"We don't know at this point the extent of their plans. We do not know their motivations," he added.

"It is possible that this was terrorist related. But we don't know. It is also possible that this was workplace related," he said.

Gunmen shot down 14 people on Wednesday at a Southern California social services center and injured 17 others. According to local police, "some degree of planning" was involved in the worst mass shooting of the year.

After a tense afternoon chase, two armed suspects were killed by police.

In his brief speech on Thursday, Obama assured the Americans that the authorities would get to the bottom of what happened, adding that the Federal Bureau of Investigation had took charge of the case.

Obama renewed calls for stricter gun control policy and said all Americans "have a part to play" in stopping gun violence.

It was the second mass shooting in six days. On Friday, a shooter attacked a Planned Parenthood facility in Colorado, killing three and unjuried several more.