Four people were trapped after an eight-storey building under construction partially collapsed at Ole Nairi area in Oloolua, Kajiado North, officials said.
The incident happened on Saturday morning, officials from the National Disaster Management Unit said.
Police said they had joined the rescue mission.
The emergency response team together with police said the situation was worsening and needed to be handled with extreme caution as efforts continue to rescue the four believed to be trapped beneath the rubble.
Authorities warned that the remaining section of the building was at risk of further collapse. They said that it poses a major challenge to the ongoing operation.
Heavy rains being experienced in the area are also hindering the rescue mission. Residents called for a faster response process in hopes of saving those still trapped.
Kenya Red Cross said a multi-agency response team was on site conducting rescue efforts, supported by an excavator.
This is the latest of such incident amid efforts to address the menace in the construction sector.
Dozens of people are annually killed in such tragedies. There are calls for parties to follow rules for safety of workers in such situations.
Corruption and lack of supervision has been blamed for the deaths and injuries at the sites. Authorities also never take action on those involved in the construction of collapsed structures.
Collapsed building structures are also failures in part or all of a building system due to overload, poor design, material failure, construction defects, environmental forces, or lack of maintenance.
Common warning signs of structural instability include large widening cracks in walls or columns, tilting structural members, sagging floors or roofs, unusual vibrations, and snapping, creaking, or crushing sounds coming from the building structure.
