It's understood five people are dead and a number of other Irish students are critically injured.
The incident happened shortly after midnight local time in the university city of Berkeley in California.
The fourth floor balcony of an apartment building collapsed onto the pavement on Kittridge Street near the University of California, killing five people and critically injuring at least 8 others.
Emergency services are at the scene and the area around the building has been sealed off – authorities say they do not know at this stage what caused the collapse.
The Minister for Foreign Affairs Charlie Flanagan has described the incident as a “dreadful accident”, confirming that all five of those who died were Irish.
He has activated his Department's Consular Crisis Centre to help the families of the victims and the Consul General in San Francisco is in close contact with the authorities.
An emergency response line has been opened – anyone with concerns about friends or family in the region, should call 01- 418 0200.
