28. (1) Subject to the other provisions of this section, a person shall forfeit forthwith his Nigerian citizenship if, not being a citizen of Nigeria by birth, he acquires or retains the citizenship or nationality of a country, other than Nigeria, of which he is not a citizen by birth.

(2) Any registration of a person as a citizen of Nigeria or the grant of a certificate of naturalisation to a person who is a citizen of a country other than Nigeria at the time of such registration or grant shall, if he is not a citizen by birth of that other country, be conditional upon effective renunciation of the citizenship or nationality of that other country within a period of not more than five months from the date of such registration or grant