Four people died when a building collapsed in central Tbilisi on Monday. Witnesses say there were workers there during the collapse, the Democrary and Freedom Watch reports.

Rescuers are looking for one more worker in the collapsed building located in the Saburtalo district, behind the Sports Palace. It was built during the Soviet Union and was used by the Institute of Mathematics, but was recently sold and refurbishing is under way with plans to open a hotel there.

The reasons of the collapse are not yet known. However, experts have said many of the buildings being constructed in this area don’t meet safety standards and might be dangerous.