Dozens of children trapped in collapsed Lagos building
The children were attending an "illegal school" inside the residential building when the structure collapsed, officials said.
"Dozens of children were trapped inside," said Adesina Tiamiyu, head of Lagos state emergency management agency (SEMA), which is supervising the rescue operation.
More than 4 dead bodies
But they had also recovered "more than four dead bodies", Tiamiyu said without giving an exact figure.
Police said they believed scores of people were trapped under the rubble of the building which collapsed mid-morning in an area near Itafaji market on Lagos Island.
Punishment for the people responsible
And he promised a full investigation, pledging there would be "punishment" for anyone found responsible for the building's collapse.
In chaotic scenes, panicked parents, local residents and shocked onlookers rushed to the area as police, firemen and medics staged a massive rescue operation.
"Please, save my child!"
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.
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.
Building collapse common in Nigeria
In September 2014, 116 people died -- 84 of them South Africans -- when a six-storey building collapsed in Lagos where a celebrity televangelist was preaching.
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.(With text inputs from AFP)