Rescue workers in Lagos, Nigeria, continued efforts Tuesday to extricate survivors and recover bodies after the Monday collapse of a 21-story apartment building that was under construction.

“We have recovered more bodies. The death toll now stands at 15, while nine were pulled out alive,” Ibrahim Farinloye of the National Emergency Management Agency told the French news agency, AFP.

President Muhammadu Buhari called on the search teams to speed up the rescue effort. Dozens of people are reported missing.

The cause of the collapse is still not known, but Lagos emergency management agency manager Femi Oke-Osanyintolu told AFP there were problems with the construction.

“We are going to get to the roots of the matter to prevent a recurrence,” he was quoted as saying.

The building was located in the affluent Ikoyi district where building construction is booming. Built by developer Fourscore Homes, the cheapest apartment was listed as selling for $1.2 million.

The company said 65% of the units had been sold with occupants expected to move in next year.

In 2004, a building collapse in Lagos killed more than 100 people. In 2016, 60 people were killed when a church roof collapsed in the eastern city of Uyo.

Source: Voice of America