CAPE TOWN, May 8 (Xinhua) -- The number of people killed in the collapse Monday of a building under construction in South Africa has risen to seven, with 39 still missing, authorities announced on Wednesday. The multi-story building collapsed Monday afternoon in the coastal city of George, located about 400 kilometers east of Cape Town in the Western Cape province. The reasons for the collapse of the building, which included an underground parking garage, are still under investigation. Thirty-six people have been retrieved by rescuers from the rubble, as the rescue operation is approaching 49 hours as of 14:30 this afternoon, May 8, said the municipal government of George in its latest update. Of those 36, seven have been declared deceased while 16 others are in a critical condition, according to the municipality. A total of 39 of the initial 75 workers on site remain unaccounted for at present, it said. Rescue operations at the building site continue with a multidisciplinary rescue team of more than 200 emergency services staff from across the province, according to a statement issued by the Western Cape government. Western Cape Premier Alan Winde offered condolences to the families of the deceased and thanked all individuals and organizations involved in the rescue and emergency response efforts. My heart goes out to the families of the deceased. I share your pain. We will do everything we can to ensure we determine the exact cause of this incident, the statement quoted Winde as saying. Our teams on the ground are working tirelessly to rescue the remaining 39 individuals, he said. We must not give up hope.