The collapse of the Berkeley apartment balcony was like "a really big earthquake" which left the complex shaking, a witness has revealed.
Silvia Biswas lives on the third floor of Library Gardens, one floor below the collapse, and said she called emergency services immediately when she looked out and saw bodies on the ground.
"When the balcony was falling down, we thought it was an earthquake, and a really big earthquake. It was shaking my window. It was kind of like the building was falling down," she told the New York Times.
J1 students living in the area have been inundated with calls from loved ones to check on their whereabouts and safety, and the Irish Immigration Pastoral Centre in San Francisco are organising for families to come over as soon as possible.
A man makes the sign of the cross over his heart after laying a bouquet of flowers near the scene of a 4th-story apartment building balcony collapse in Berkeley, California June 16, 2015. Six people were killed, including five young Irish citizens, and at least seven other people were injured when an apartment balcony collapsed early on Tuesday in the Californian city of Berkeley, Ireland's foreign minister said. REUTERS/Elijah Nouvelage
"Our pastor is at the hospital with some of the victims, and another one of our staff is there in Berkeley. We're absolutely inundated with queries from people looking to get information on friends and family and a lot of volunteers are offering help," said co-ordinator Joan Cuddihy.
"We've been in contact with a lot of families, who are looking to come over straight away, so we're trying to organise for them to be picked up and accommodation at the moment," she added.
Another student, who recently arrived in the US, came close to the scene on her way home from work in the early hours of Tuesday morning.
"I went past it as I was coming home from work, there was around seven or eight ambulances and loads of police cars at the scene. I was on my own, so I didn't stop to see, and didn't actually think much into it," she told the Herald.
"I got calls and texts from my mam, my sister and some of the girls that I know over here and that's gone on all day. Everybody is texting each other because it could have been anyone. It's really sombre here at the moment, one of the girls that lives here is actually gone to see if she can find out if any of her friends were involved, because she heard some of the people at the party were from Foxrock," she added.
Two Irish students who are staying in the Berkeley area told RTE that they were "shocked" by what they saw.
Mark Neville said he was on the first floor of the building at the time.
The remains of a damaged balcony are removed from a 4th-story apartment building balcony in Berkeley, California June 16, 2015. Six people were killed, including five young Irish citizens, and at least seven other people were injured when the balcony collapsed early Tuesday in the Californian city of Berkeley, Ireland's foreign minister said. REUTERS/Elijah Nouvelage
"Everyone was just really shocked, our thoughts are with the families back home, really its just tragic," he said.
Dan Sullivan said he saw rubble all over the ground outside the apartment complex.
"I came out at midnight and I saw Irish people in tears," he said.
David Smith is living on Blake Street, just over a kilometre from where the deaths occurred. He said he's relieved none of his friends are hurt.
"We were actually at a different 21st party on Monday night, so it's a major shock. We've been checking with others too, to see if they're okay, because we're only a five-minute walk from Kittredge Street," said Mr Smith.
"We all woke up with missed calls in the middle of the night and we've been getting loads of texts and calls since, so we've got very little sleep with all the panic," he said.
Eyewitness Alan Weddington arrived at the scene five minutes after the incident and spoke to Joe Duffy on RTE Radio One.
"There were emergency crews and a lot of people, some crying and some running. On the ground, you could see the concrete from the balcony, and then some clothes, shoes and the people on the ground. It was a horrific scene out there," Mr Weddington said.
"I think everybody is puzzled about how this happened in a reasonably new complex. Everybody is just surprised at how this could happen," he added.
Another witness passing by took some of the injured victims to the local hospital.
"They were all just talking amongst themselves frantically trying to find out who was on the balcony and who wasn't on the balcony, and who might have been injured and who might not have been injured, that was their whole focus.
"One woman had blood on her knees and one guy had blood on his shirt," he said.