Establishment and composition of the armed forces of the Federation
Section 217(2)(c) · 1999 Constitution (2004 edition)
What Constitution says
(c) suppressing insurrection and acting in aid of civil authorities to restore order when called upon to do so by the President, but subject to such conditions as may be prescribed by an Act of the National Assembly; and
This is the 1999 Constitution as published in 2004. Later amendments aren't included yet, so a section may have changed since.
Original source
Official Gazette · CFRN 1999 official PDF · printed page 97. Original document
Release: draft-c8d50d87fae9. Source scope, review and corrections