Smoke was seen billowing from the Kenyatta International Convention Centre (KICC) on Wednesday mid-morning sending panic waves among passers-by.
Some took to social media platforms to raise alarm but later authorities from the building assured Kenyans that all was well and that they were conducting a fire drill to test its preparedness in case of an emergency.
The premise is set to host the third edition of China Trade Week Kenya on Thursday and it is believed that the drill was done in preparation for the event.
The drill was conducted by the St John Ambulance disaster preparedness & response crew and the Nairobi County fire brigade.
In 2015, an employee of Strathmore University died after she jumped from the third floor of a building during a security drill.
Esther Rusha Kidambi, 33, who worked in the catering department, died at the University dispensary.
The drill had been organised by the university and security agencies to test the students' alertness and response.
The mock operation, however, went bad when some students, who were not aware of it, jumped from as high as the fourth floor, thinking they were under attack.
