U.S. and Hawaii state flags are flying at half-staff to honor the victims of the shooting in California that left 14 people dead.

The White House says President Obama signed a proclamation today calling for flags to remain at half-staff through Monday and affects flags at the White House, public buildings, military installations, U.S. Navy ships, embassies and diplomatic missions.

Hawaii Gov. David Ige also issued a proclamation ordering state flags be flown at half-staff until sunset.

“Our hearts are heavy with grief for the victims of this senseless act of violence and our thoughts are with their families, colleagues and friends. We mourn along with the San Bernardino community,” Gov. Ige said in a news release.

Obama said it’s possible the massacre was related to terrorism but that authorities still don’t know. He says it’s possible it was workplace-related or that there were mixed motives.

Authorities say Syed Farook and his wife or fiancee killed 14 people at a social service center Wednesday before dying in a gunbattle with police. He fired on colleagues at a holiday gathering for county health employees.