At least 16 people dead and numerous missing after building collapse in Lagos.

Nigerian officials have called off search-and-rescue efforts a day after a building, with a school on the third floor, collapsed in Lagos with an unknown number of people inside.

On Thursday, National Emergency Management Agency official Ibrahim Farinloye told The Associated Press that the workers had reached the foundation of the collapsed building and did not expect to find more people.

Rescue workers with the Red Cross told Al Jazeera their team left the site of the accident at 3pm local time (14:00 GMT).

The decision to call off the search was protested against by some anguished families.

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At least 16 people are thought to have died but the toll could rise.

Farinloye declined to give updated numbers for the dead and missing. Late on Wednesday, officials said 53 people were freed and an unknown number of people are still missing.

“Emergency workers are moving material out of the location because they believe the operations are over, but the locals insist that operations must continue because they believe that there are many people still trapped under the rubble,” said Al Jazeera’s Ahmed Idris, reporting from the scene.

The exercise was declared concluded after the emergency officials reached the “Grand Zero” of the site of the incident (meaning that all the rubbles/debris had been evacuated and there is no evidence that anyone is still trapped), #ItesiwajuIpinleEko #LASG #LRU #LagosRescue pic.twitter.com/nVBUfV15Nz — The Lagos State Govt (@followlasg) March 14, 2019

A crowd of thousands of people cheered on Wednesday as dust-covered, shocked-looking children were pulled from the rubble.

It is not yet known what caused the collapse of the building, which stood in a crowded neighbourhood at the heart of Nigeria’s commercial capital.

Building collapses are frequent in Nigeria, where new structures often go up without regulatory oversight.

Lagos State Governor Akinwunmi Ambode said the building, which had been marked for demolition in 2017, was classified as residential and that the school was operating illegally.

Residents are continuing the search, convinced there are more bodies under the rubble [Afolabi Sotunde/Reuters]

It also housed shops, offices and residential units.

Ambode added that property owners in the area defied demolition notices, adding that most of the buildings in the area had been marked for destruction.

In a Twitter post on Wednesday, Nigerian President Muhammadu Buhari said he was “extremely saddened” by the incident.

I’m extremely saddened by the news of the collapsed building in Itafaaji area of Lagos. It touches one to lose precious lives in any kind of mishap, particularly those so young and tender. May God grant everyone affected by this sad incident fortitude and succour. — Muhammadu Buhari (@MBuhari) March 13, 2019

“It touches one to lose precious lives in any kind of mishap, particularly those so young and tender,” Buhari said, urging the state government to do “all that is needful, so that such tragic developments do not recur”.

Obiora Manafa with the Standards Organization of Nigeria told reporters that they would analyse samples of the collapsed building’s steel bars and concrete “to ascertain the quality … and know whether they complied with the national building code.”

Additional reporting by Shayera Dark in Lagos