CAPE TOWN, South Africa (AP) — Rescue teams in South Africa forged ahead Monday with efforts to find any survivors still trapped under rubble a week after an apartment building that was under construction collapsed.

Their hopes were boosted over the weekend when one of the construction workers was found alive after six days without food and water.

Authorities said 24 construction workers who were on the site when the unfinished five-story building came down have been confirmed dead, while another 28 are missing, raising the possibility that the death toll could ultimately be above 50.

More than 600 emergency services and other personnel have been involved in the search for survivors in the wreckage of the building in the city of George on South Africa’s south coast, which collapsed last Monday.

There were 81 workers on the site when it collapsed, and 29 have been pulled out alive, the city said. It said 13 of them remained in a hospital without giving details of their condition. The city has previously said that many of the survivors were in critical condition when they were found.