Seven other people were seriously injured. Berkeley police spokeswoman Jennifer Coats said the survivors’ injuries were “very serious and potentially life-threatening”.
The victims, who had travelled to the United States on J-1 summer visas, fell from the fourth floor of an apartment building when the balcony gave way at 12.40am on Tuesday.
Four died at the scene and two others were pronounced dead at a local hospital, police said.
Pictures from the scene showed the balcony detached itself from the wall and collapsed into a balcony on the third floor of the pale stucco building on Kittredge Street, near the University of California Berkeley.
The City of Berkeley has released, along with the update on the incident, the 57-page building and safety inspection history for 2020 Kittredge Street.
The collapsed balcony and the three other similar balconies in the building, have been red-tagged, prohibiting access to those areas.
The City said it had ordered the property owner to immediately remove the collapsed balcony and to perform a structural assessment of the remaining balconies within 48 hours.
Blackrock, the investment giant that advises the property fund that owns the building, and Greystar, the Texas-based company that manages it, said that an independent structural engineer would carry out an investigation to determine the cause of the accident.
Irish students who had been sleeping in the building at the time described hearing a bang. “I walked out and I saw rubble on the street and a bunch of Irish students crying,” said Mark Neville, a J-1 student.
The Irish Consul in San Francisco was quoted by NBC saying that up to 14 people were on the balcony at the time.
Those involved were aged 20-22 years old. The injured had been taken to Eden, Highland and John Muir Hospitals.
The Irish Immigration Pastoral Center tweeted on Tuesday: ‘All San Francisco based J1 students – PLEASE CALL HOME ASAP – let your families know that you are ok.’