The crash, which happened at about 8.00 pm near the Dar es Salaam Roundabout, left rescue teams, police officers and members of the public scrambling to assist victims trapped in the wreckage as concerns grew that the number of casualties could rise.
The vehicle, commonly referred to as a Detat matatu, was carrying passengers when it overturned opposite KCB Bank under circumstances that were initially unclear.
Witnesses at the scene said the matatu lost control before rolling onto its side, leaving several passengers injured while others died on the spot.
Police investigations later indicated that the matatu was travelling from the DT Dobie direction towards General Motors when a motorcycle rider, who has not yet been identified, allegedly emerged from Dakar Road and failed to give way.
According to police, the matatu driver swerved in an attempt to avoid a collision, hit the central island kerb at the roundabout, lost control and the vehicle overturned onto its left side.
The motorcycle rider reportedly fled the scene immediately after the accident.
The driver sustained a fracture on his left leg and was rushed to hospital for treatment.
Police said four people died at the scene after suffering multiple injuries. The victims included three passengers and an unidentified female pedestrian believed to be about 30 years old.
Fifteen passengers sustained injuries of varying severity and were taken to different hospitals for treatment.
The Kenya Red Cross classified the incident as a mass casualty road traffic accident and deployed emergency teams to support rescue and evacuation efforts.
“A mass casualty road traffic incident involving an overturned PSV has occurred along Enterprise Road in Industrial Area, opposite Nairobi Prison. Kenya Red Cross emergency response teams are on the scene providing first aid and evacuation support to those affected,” the organisation confirmed.
Images and videos from the scene showed emergency responders working alongside members of the public to help injured passengers as ambulances ferried victims to nearby hospitals.
Police officers visited the scene and launched investigations into the cause of the crash.
The bodies of the deceased were moved to Nairobi City Mortuary pending identification and post-mortem examinations.
Authorities are also seeking to trace the motorcycle rider believed to have played a role in the events leading up to the accident.
The crash caused traffic disruption along Enterprise Road, one of the main routes serving Nairobi's Industrial Area. The road links Mombasa Road with Factory Street and is widely used by motorists and businesses operating in the area.
The accident occurred near several key installations, including the Nairobi Remand and Allocation Maximum Security Prison, also known as the Industrial Area Remand Prison, the Industrial Area Police Station and the Enterprise Road Post Office.
As rescue operations continued, transport stakeholders renewed calls for greater safety within the public transport sector.
The Federation of Public Transport Sector (FPTS) expressed condolences to families affected by the tragedy and called for stricter discipline among operators.
“Dangerous driving, Manyoka stunts, and bus crews hanging on doors continue to place lives at risk,” the federation warned.
FPTS further stated that while nganya culture remains a visible part of Nairobi's urban transport system, it should never come before passenger safety and road discipline.
The organisation urged SACCOs and operators to strengthen training for drivers and conductors while ensuring strict compliance with safety regulations.
It also called for greater professionalism across the sector, warning that entertainment and showmanship on public roads should never come at the expense of human life.