The National Super Alliance (Nasa) says it will hold demonstrations in Nairobi on Friday in its push for electoral reforms.
The coalition has written to Nairobi County commander Japheth Koome saying its procession will be peaceful.
Through Edwin Sifuna and Associates Advocates, Nasa, however, does not mention the streets its demonstrators will use.
"Our clients intend to hold peaceful processions/ demonstrations on Friday November 10, 2017 within Nairobi County as part of its quest for electoral justice and an end to electoral impunity in Kenya," reads part of the letter.
"You are hereby notified of the same and requested to provide security during the said procession/ demonstration to ensure criminal elements do not take advantage to harm protesters, the public or any property," it adds.
On Saturday, Siaya Senator James Orengo told journalists in Nairobi that the alliance would hold one demonstration this week in its push to have a fresh presidential election held after nominations.
Demonstrations within the Nairobi Central Business District were a subject of a tug-of-war a few weeks ago when acting Interior Cabinet Secretary Fred Matiang'i outlawed them.
By writing a letter to the police, Nasa hopes officers will make the demonstration safe.
"Your cooperation towards making the peaceful demonstration a success, in line with your responsibilities under the law, will be highly appreciated," the letter states.