All least five of the dead were Irish students in the country on visas that enable young people to work and travel in the U.S. over the summer, Ireland’s foreign minister said.

Police and officials stand outside of the Library Gardens apartment complex, where a fourth floor balcony rests on the balcony below after collapsing early Tuesday morning near the University of California, Berkeley. The Associated Press

Police and fire and building officials were working to determine what caused the roughly 5-by-10-foot metal-railed balcony to break loose from the side of the stucco apartment building. It tipped downward and landed on the 3rd-floor balcony below, spilling victims onto the pavement.

“I just heard a bang and a lot of shouting,” said Dan Sullivan, a 21-year-old student from Ireland who was asleep in the five-story building. Mark Neville, another Irish student in the building, said: “I walked out and I saw rubble on the street and a bunch of Irish students crying.”

Police had gotten a complaint about a loud party in the apartment about an hour before the accident but had not yet arrived when the balcony gave way just after 12:30 a.m., police spokesman Officer Byron White said. Irish Prime Minister Enda Kenny said police told him 13 people were on the balcony.

The Library Gardens apartment complex is about two blocks from the Berkeley campus and is a popular place for students to live. After the accident, city building inspectors barred use of the balconies while they are inspected for safety.

The apartments were built in 2006, the Los Angeles Times reported. The complex is managed by Greystar Management, whose website says the company operates more than 400,000 units in the U.S. and abroad. A call to Greystar officials was not immediately returned.

Within hours of the tragedy, small makeshift memorials to the dead sprang up on the pavement.

Irish President Michael D. Higgins said that he “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. My heart goes out to the families and loved ones of all those involved.”

Jerry Robinson, who lives nearby, told San Francisco news station KGO-TV that he had just gotten out of a movie when two hysterical people flagged down his car asking for a ride to a hospital to check on injured friends.

“They were friends of the people who were on the balcony. A couple of the women did not have shoes. One of the women had blood on her knees,” he said.