BERKELEY, Calif. -- A shrine is growing tonight in Berkeley, Calif., at the scene of a terrible tragedy. Six young people were killed, seven seriously injured when an apartment balcony collapsed. The dead were college students from Ireland.

At 12:41 a.m., ambulances rushed to the building where a fourth floor balcony broke away.

"At least 10 people fell from the second or third floor," said a police dispatcher.

Students killed in balcony collapse, clockwise from top left: Eimear Walsh, 21; Olivia Burke, 21; Ashley Donohoe, 22; Eoghan Culligan, 21; Niccolai Schuster, 21; and Lorcan Miller, 21. CBS/Facebook

It happened during a late night 21st birthday party with a group of Irish students, most of them visiting on summer work visas.

"It was just a loud crash and silence for a couple of minutes," said Owen Buckley, a student from Ireland who heard the commotion from his third floor apartment. "We were sure someone was shot, and then we find someone on the stairs saying the balcony just collapsed. That is what happened."

At least 13 people were on the balcony which appeared to peel away from the building, landing upside down on the balcony a floor below, spilling victims 50 feet onto the street.

Debris from a collapsed balcony accident in Berkely, Calif. Authorities have not establised a cause of the failure. CBS News

"I looked down and it was just death," said Jason Biswas who lives in the building with his parents. "I was in the presence of a lot of death. I didn't want to stay there for too long."

The students are visiting on the popular J-1 visa program which allows foreign students to work and travel in the U.S. during the summer.

In Ireland the deaths and injuries are seen as a national tragedy.

"It is truly terrible to have such a serious and sad incident take place at the beginning of a summer of adventure and opportunity for so many young people on J1 visas in the US," said Irish Prime Minister Enda Kenney.

An official cause of this accident has not yet been established. But city inspectors have closed all the other balconies in this eight-year-old building until they know more about why this happened.