Police said five people died and eight others were wounded when a fourth-floor balcony collapsed early Tuesday in Berkeley, California.
Several of the victims were young Irish nationals, according to Ireland's government.
Berkeley Police spokeswoman Jennifer Coats told NBC News the balcony fell to the sidewalk from the top of the four-story building shortly after midnight local time (3 a.m. ET). She said Berkeley Fire Department and city officials are on scene, adding that officials have secured the area around the collapse and have not evacuated the building.
The injured were being treated at area hospitals and authorities do not know what caused the collapse, Coats said.
A "number of young Irish citizens" were among the dead while "a number of others" were seriously injured, according to Ireland's Department of Foreign Affairs.
"It is too early to know the full extent of this dreadful accident," it said in a statement, adding that Ireland's consul general in San Francisco was in touch with authorities and providing assistance to those affected.
The building where the collapse occurred is just two blocks from the campus of the University of California, Berkeley, according to NBC Bay Area.
This is a breaking news story, please check back for updates.