The incident happened near structures that were being demolished on riparian land, according to Kenya Red Cross, which is leading rescue operations alongside other emergency responders.

In a brief statement, the humanitarian agency said the collapse occurred next to buildings that had been earmarked for demolition due to their location on a river reserve.

"A building has collapsed in the Blue Estate area of Shauri Moyo, adjacent to structures that were being demolished on riparian land. An unconfirmed number of people are feared trapped in the rubble," the Red Cross said.

Rescue teams have since been deployed to the site, with efforts focused on searching through the debris to locate anyone who may be trapped.

The Kenya Red Cross said rescue operations are ongoing and promised to provide more updates as the situation develops.

"Updates to follow," the agency said.