LAGOS: A high-rise building under construction collapsed in Nigeria's commercial capital Lagos on Monday, killing at least four people with dozens more feared trapped inside the rubble. A yellow excavator pushed away concrete slabs to search though the wreckage of the 21-floor building in Lagos's wealthy Ikoyi residential and business district, AFP correspondents at the scene said.

Rescue officials said many workers were caught inside the building when it crumbled, though they could not confirm the number of people trapped inside.

Ibrahim Farinloye of the National Emergency Management Agency (NEMA) said four people had been rescued so far and four bodies recovered from the site. Wisdom John, 28, a bricklayer, told AFP he escaped with just a few cuts because he had been on the ground floor when the building collapsed into a pile of concrete, its floors sandwiched together.

"There was more than 50 working today and the manager too," he said, sitting in an ambulance getting treated. "We just ran out."

The Ikoyi area is one of the wealthier residential and business districts in Lagos, Nigeria's densely populated major commercial city. Near the collapse site, soldiers kept back a crowd of onlookers watching the rescue operation.