Authorities have not yet been able to give a final death toll after the four-storey building housing the school, homes and shops collapsed on Wednesday.
Tolls given on Wednesday ranged from one to eight dead and between 37 and around 50 recovered alive, but on Thursday a spokesman for the national emergency agency said some of those presumed dead had been revived and the figures were in flux.
Children shoes are seen among the ruble of a building collapse in Ita Faji, Lagos. Source: AAP
Residents say the school alone had around 100 pupils. Rescuers were trying to find a register to work out how many of them may have perished, an emergency official said.
At the hospital, 50-year-old hairdresser Arike Kuye waited for news of her granddaughter, aged seven, who has being treated for a head injury.
Her 11-year-old granddaughter was killed in the accident.
"I've been here for hours. I don't know how long it has been," she said, as her eyes filled with tears.
Around two dozen people, mostly women, were gathered outside the wing where hospital officials said seven children were being treated.
At the site of the collapse on Thursday morning, people searched through the tangle of rubble and metal to find any belongings of their loved ones.
By the afternoon, most of the debris had been cleared away.
"We have been able to pull down the remaining part of the building," said Adebayo Kayende, spokesman for the Lagos state emergency agency.
"We have moved the debris from the ground to have a clear picture to make sure there are no people under the building."
Kayende said the Lagos state ministry of health was checking with hospitals and once they had finished counting those dead the details would be made public.
Lagos Governor Akinwuni Ambode, who visited the site hours after the building collapsed, said the school had been set up illegally and that buildings in the area had been undergoing structural testing prior to the accident.
There will be a full investigation into the incident, he said.
Blood and dust
A young man helping rescue efforts who gave his name only as Derin said "at least 10 children" were trapped inside but "thought to be alive".
An AFP reporter at the scene saw at least eight people pulled from the wreckage, including a small boy with blood on his face.
People help a child after he was rescued from a collapsed building in Lagos, Nigeria. Source: APP
Covered in dust, he was alive but unconscious and appeared to be badly hurt.
One local resident who witnessed the moment of collapse said there was no warning.
"We were smoking outside when the building just collapsed," Olamide Nuzbah told AFP in pidgin English.
A woman cries as the body of a child is recovered. Source: APP
Distraught parents
As rescuers worked furiously to reach those inside, distraught parents begged them to find their children.
"Please, save my child, save my child!" wept one traumatised mother whose seven-year-old daughter was trapped inside, as people tried to console her.
School bags, toys and clothes could be seen among the piles of rubble as a bulldozer tried to clear a path through some of the wreckage to help the rescue efforts.
As the day wore on, several children were brought out, at least one of whom appeared to be dead.
Elsewhere, hundreds of local residents tried to help, passing water and helmets through to dust-covered rescuers working tirelessly to sift through the rubble, some of whom appeared to be distressed.
Many locals said that the building, which was in an advanced state of disrepair, had been "earmarked" for demolition by the authorities in Lagos state.
"It is a residential building that was actually accommodating an illegal school," said Ambode, the state governor, confirming that most buildings in the area had been marked for demolition but saying some landlords had defied the move.
Emergency workers attend the scene. Source: AP
"We get resistance from landlords but we must continue to save lives," he said, pledging to step up measures against all structures that failed to meet the correct standards, saying they would be "quickly evacuated" and demolished.
Lagos, which has a population of 20 million people, is made up of a collection of islands.
One of them is Lagos Island, a densely-populated area which is one of the city's oldest neighbourhoods.
It is characterised by its Afro-Brazilian architecture, a style brought over by thousands of freed slaves who headed back home after decades working the plantations in Brazil.
A woman cries as a body of child is recovered from the rubble of a collapsed building in Lagos, Nigeria. Source: AP
Tragically common
Despite efforts to renovate the area, a large number of abandoned buildings have been taken over by families or businesses, despite being dilapidated and unsafe.
Building collapses are tragically common in Nigeria, where building regulations are routinely flouted.
In September 2014, 116 people died when a six-storey building collapsed in Lagos where a celebrity televangelist was preaching.
Rescue workers and emergency teams rush to the scene. Source: APP
An inquiry found it had structural flaws and had been built illegally.
And two years later, at least 60 people were killed when the roof collapsed at a church in Uyo, the capital of Akwa Ibom state, in the east of the country.
