At least eight people have have died and dozens of children are trapped after the collapse of a four-storey school building in Nigeria.
"Thirty-seven people were rescued alive and eight were recovered dead," Ibrahim Farinloye of the National Emergency Management Agency (NEMA) said in a statement.
The trapped children were attending an illegal school inside the residential building when it collapsed, officials said.
Emergency workers had pulled people alive from the rubble, some of them badly injured, said Official Shina Tiamiyu, head of the Lagos state emergency management agency.
Police said they believed scores of people were trapped under the rubble of the building that collapsed in mid-morning in an area near Itafaji market on Lagos Island.
"We are getting additional cranes to be able to go deeper than where we are now to rescue more lives," Lagos state governor Akinwunmi Ambode said.
Mr Ambode promised a full investigation and promised punishment for anyone found to be responsible for the tragedy.
Panicked parents, local residents and shocked onlookers rushed to the area as police, firemen and medics began a rescue operation.
It was not immediately clear how many people were inside when the building fell.
One health official said 20 people had been taken to hospital.
"We are still trying to find out how many are trapped inside," police officer Seun Ariwyo said.
Derin, a young man helping rescue workers, said at least 10 children were trapped inside but they were believed to be alive.
Those pulled from the wreckage included a small boy with blood on his face, AFP reported. He was alive but unconscious and appeared to be badly hurt.
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 daughter, 7, was trapped inside.
Schoolbags, toys and clothes were among the piles of rubble as a bulldozer tried to clear a path through wreckage to help the rescue workers.
Hundreds of locals tried to help, passing water and helmets through to dust-covered rescuers, some of whom appeared to be in distress as they sifted through the rubble.
Many locals said the building, which was in an advanced state of disrepair, had been set aside for demolition by the authorities in Lagos state.
Mr Ambode said most buildings in the area had been marked for demolition but saying some landlords had defied the order.
"We get resistance from landlords but we must continue to save lives," he said.
Mr Ambode pledged to improve 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 a collection of islands.
One of them is Lagos Island, a densely populated area which is one of the city's oldest neighbourhoods.