Story highlights Irish official says family members will begin arriving in U.S. on Tuesday night

Five of people killed were from Ireland, police say

They were celebrating someone's 21st birthday, Irish foreign minister says

(CNN) An apartment balcony collapsed during a birthday party attended by Irish students in the California city of Berkeley early Tuesday, killing six of the 13 people who fell from the fourth-floor structure, officials said.

Three men and three women in their early 20s died following the collapse, officials told reporters. Five of the victims were from Ireland and one was from California, said Sgt. J.D. Nelson of the Alameda County Sheriff's Department.

Those Irish citizens who fell from the balcony at the Library Gardens Apartments were students with short-term work visas, gathered in an apartment to celebrate someone's 21st birthday, Irish Foreign Minister Charlie Flanagan said earlier.

At an afternoon news conference, Nelson released their names: Olivia Burke, 21; Eimear Walsh, 21; Eoghan Culligan, 21; Niccolai Schuster, 21; and Lorcan Miller, 21.

Ashley Donohoe, 22, from Rohnert Park, California, was also killed.

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