Five Irish students and one other young woman have been killed after a fourth-floor balcony collapsed at a US apartment.

Authorities in California confirmed that seven others remain in hospital.

The collapse happened during a 21st birthday party shortly before 01:00 local time (08:00 GMT) on Tuesday in the city of Berkeley.

The students are believed to have been living temporarily in the US as part of a work exchange programme.

Around 700 Irish students are currently living in the San Francisco Bay Area, said Philip Grant, the Consul General of Ireland to the Western United States.

"We're still in an emergency response mode," he said. "It's a formative experience, and to have this happen ... has left us all frozen in shock and disbelief".

Berkeley City Mayor Tom Bates described the incident as a "shocking set of events".

"We're all sort of awestruck by the incredible tragedy," he said.

The victims

- Ashley Donohoe, 22

- Olivia Burke, 21

- Eoghan Culligan, 21

- Niccolai Schuster, 21

- Lorcan Miller, 21

- Eimear Walsh, 21

Police began receiving emergency calls about the incident around 00:41 local time. The police chief said it took patrolmen about two minutes to arrive on the scene.

The cause of the collapse is still under investigation, but the city's police chief said there was no indication of any criminal activity at this point.

Photos taken at the scene appear to show a 5ft x 10ft (1.5m x 3m) balcony on the fourth floor of the building fallen on to the balcony on the level below.

Two Irish students who were asleep in the building when the incident occurred described a loud sound when the balcony fell.

"I just heard a bang and a lot of shouting," said Dan Sullivan.

Another student, Mark Neville, said: "I walked out and I saw rubble on the street and a bunch of Irish students crying."

Enda Kenny, the Irish Prime Minister, said that police had told him there were 13 people on the balcony when it collapsed.

Irish Foreign Minister Charlie Flanagan said that four of the victims died at the scene and another died in hospital.

The Alameda County coroner's office later told the BBC a sixth person had died in hospital.

The foreign minister has said that the families of all of those who died have been contacted.

University College Dublin President Andrew Deeks said late Tuesday that the accident involved students from the university and their friends.

"We cannot comprehend the desperate shock and grief they are feeling and we are heartbroken at their suffering and loss," he said. "We know the local Irish community has been offering assistance and solidarity and we thank them for this."

Berkeley Police spokesman Byron White said first responders described the scene as "quite disturbing".

Many of those hurt have life-threatening injuries, said Jennifer Coats, a Berkeley Police Department spokeswoman.

Police received a complaint about loud noise at the flat about an hour before the balcony collapsed, but did not go to the building to investigate.

The city's police chief said that the noise complaint was treated as a low priority, and noted that police officers were responding to several other emergency calls at the time - including one for shots fired in another part of town.

Irish President Michael Higgins said that he had "heard with the greatest sadness of the terrible loss of life of young Irish people and the critical injury of others in Berkeley, California today".

He said his heart goes out to the families and their loved ones.

The Irish consul general in San Francisco is helping those affected and there is an Irish helpline (+353 1 418 0200).

The apartment building was constructed in 2006, according to the Los Angeles Times.

A Berkeley city official said that building inspectors had visited the building on Tuesday. Three remaining balconies on the building have been closed.

In 2013, a similar accident killed 13 people and injured at least 50 others in Chicago, when a deck holding revellers collapsed.

In that incident, more than 60 people were on the building's porches, according to CBS Chicago.