"To ensure that criminal elements do not interfere with our festivities, we wish to remind the general public it is necessary to remain alert," Deputy Police Commissioner Francis Okonya said in a statement.
"Terrorism has been a security threat for most of this year, whereas the government has put in place extensive measures to guarantee security, we would like to advice the public to continue with vigilance during this season."
Authorities warned people participating in vigils and other gatherings associated with Christmas to remain alert at all times, Capital FM reported.
"Churches and other groups wishing to hold overnight vigil to mark the birth of Jesus Christ and the New Year are strongly advised to liaise with the local police formations for security arrangements," the police statement said.
There has been an uptick in terrorist activities, particularly in Nairobi, Mombasa and the border towns of Garissa and Mandera where security forces and civilians have both been targeted, Capital FM said.
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