Bomb experts on Thursday found an explosive in the Dusit office park where terrorists stormed on Tuesday in an attack that left 21 people dead.
Through their Twitter handle, the National Police Service (NPS) urged the public not to be alarmed if they hear a blast when their officers detonate the device.
"We wish to inform the general public that bomb experts from the @DCI_Kenya[Directorate of Criminal Investigations] are still combing the scene of the Dusit incident for any remaining explosives or booby traps that could have been left by the slain attackers," said NPS.
The Interior Cabinet Secretary Fred Matiang'i on Wednesday declared the Dusit area an active crime scene as security officers piece gather information to pursue those who funded the attackers.
All the attackers who stormed the 14 Riverside Drive building were killed.
More than 700 people were evacuated in the two-day siege.