Five people died and eight were left injured when a balcony collapsed at a building near the University of California (UC) - Berkeley early Tuesday morning.

According to the Los Angeles Times, Irish government officials confirmed all the victims were citizens and students, but it is not clear if any were enrolled at UC - Berkeley. Four were reportedly pronounced dead at the scene and another died at a hospital, while all eight of the injured are in critical condition.

Some of the students were in the U.S. on work visas and were living in an apartment building about 10 years old. The building is mostly inhabited by UC - Berkeley students, but it also houses visitors like the Irish students.

The Times and multiple other news outlets confirm the students were celebrating someone's 21st birthday at the time of the balcony's collapse around 12:41 a.m. The balcony was on the fourth floor and police still do not know what caused the collapse.

"We don't know what happened. Officers on scene talking with people," Jennifer Coates, a spokeswoman for the Berkeley Police, told NBC Bay Area. "This was a traumatic scene. Our officers and paramedics responded very quickly. They did what they could to help as many people as they could. It's going to be a very sad day for a lot of these victims' families to get this kind of news."

The Irish Examiner noted the Irish government created an emergency hotline for families at home with children or loved ones in the U.S. to call if they fear for their safety.

"It's an appalling tragedy, an appalling loss of life for young people whose hopes and dreams of the future have suddenly and without notice been shattered," the Examiner quoted Irish Minister for Foreign Affairs and Trade Charlie Flanagan saying at a press conference. "There are a number of other students in the apartment at what I understand to have been a 21st birthday party who have been injured. They are being treated at a nearby hospital.

"I understand from both the police and indeed the hospital that five Irish citizens have lost their lives."