Usman Baba has been decorated as the acting Inspector-General of Police (IGP).
The decoration ceremony which was performed by the Vice President Yemi Osinbajo took place inside the Presidential Villa on Wednesday.
Alkali was before his appointment a Deputy Inspector-General of Police.
The Minister of Police Affairs, Mohammad Dingyadi, had on Tuesday announced that Alkali has been appointed to succeed Mohammed Adamu.
Adamu, whose tenure ended in February after completion of his mandatory 35 years of service, got a three-month extension by the President but he had only spent about two months out of the three-month extension when he was replaced.