A two-year-old girl plunged to her death from a fourth floor balcony after glass panelling protecting children from the 60ft fall was missing.
Rayaheen Banimuslim was killed when she fell from the city centre complex in Sheffield, South Yorkshire, on Wednesday afternoon.
The girl's father, Hikmat, told BBC Radio Sheffield: "My wife called me and told me that our daughter had landed from the fourth floor. There is a small garden on the fourth floor of this building. When she feels the weather is nice she always takes them to play in this garden.
"What happened is that the wall of this garden is made of glass panels and some of these glass panels are missing. Rayaheen, my daughter, has fallen down from this."
Mr Banimuslim added: "There were always missing glass panels from time to time and no-one came to repair them, unfortunately this one my wife didn't see.
"It is the responsibility of the agency which manages this building. They have to replace the panels in this garden because this is the only garden the children have to play in and they have to make it more secure to save children."
Family friend Baseem Alsabbagh, 36, said the girl's mother was close by, but was unsure if she witnessed the fall. He said the family was from Iraq and Mr Banimuslim was studying for a PhD at Sheffield Hallam University. He said the family moved to the block of flats last September.
He added: "They are heartbroken. She was a lovely, beautiful baby. I can't describe it. They are heartbroken. They never expected this to happen. They are in shock. They can't believe what has happened."
He said there were "important questions" to answer regarding safety on the balcony and missing glass panels. "They should have been fixed, there should be extra safety up there."
But he added: "I think the family are only thinking about taking their daughter back to Iraq. She was lovely and beautiful and always playing. We have happy memories of her."