CAPE TOWN, South Africa (AP) — Rescue teams worked through the night searching for dozens of construction workers buried for more than 12 hours under the rubble of concrete after a multi-story apartment complex that was being built collapsed in a coastal city in South Africa.

Authorities said early Tuesday that the death toll had risen to five, while 49 workers remained buried in the mangled wreckage of the building, which collapsed on Monday afternoon. Authorities said a further 21 workers had been rescued from the rubble and taken to various hospitals, with at least 11 of them suffering severe injuries.

The collapse happened in the city of George, about 400 kilometers (250 miles) east of Cape Town on South Africa’s south coast.

More than 100 emergency personnel and other responders were on the scene, using sniffer dogs to try to locate workers, some of whom were trapped under huge slabs of concrete that fell on them when the five-story building came down.