The Inspector General of Police says the militia causing crisis in some parts of the country, are being armed with the help of some police officers.
Ibrahim Idris met with senior officers at the force headquarters in Abuja.
He said no state has the right to approve prohibited fire arms to anybody, but also added that arrests have been made concerning the recent killings of ethnic Fulanis in Benue.
Idris also ordered state Commissioners of Police to, as a matter of urgency, disarm all militias, vigilantes and other armed protective units set up by state governors across the country.
The IGP, who made it clear that it was the responsibility of the police to provide security for citizens of Nigeria, said: “everybody is aware we are entering a very tedious and serious situations in this country.
“Political issues are coming up to the fore and I believe officers must gear up in our various locations, in our various responsibilities to ensure that we provide law and order all over Nigerian,” he said.