Lima, America: otherwise called an African city (6)
I believe the answer is:
lusaka
'an african city' is the definition.
(capital of Zambia)
'lima america otherwise called' is the wordplay.
'lima' becomes 'L' (phonetic alphabet: alpha, bravo, charlie etc.).
'america' becomes 'US' (United States).
'otherwise called' becomes 'aka' (also known as).
'l'+'us'+'aka'='LUSAKA'
(Other definitions for lusaka that I've seen before include "Zambian capital" , "Zambian city" , "Central African capital" , "African capital - UK alas (anag)" , "Capital of Zambia" .)