The Ghana under-17 winger was a subject of speculations ahead of the 2017 Fifa Under-17 World Cup in October, having been reported to have signed a deal with the Citizens amid interest from the likes of Real Madrid and Bayern Munich.
Wafa, however, denied any done deal, and the attacker's nondescript showing at the youth championship seems to have killed the rumours surrounding his future.
“Manchester City are still interested in Aminu," Ofusuhene told Citi FM.
"We are still in negotiation with them [Manchester City], but because he is a minor he cannot make a transfer to any club until he is 18.
"He is currently training with Man City and a transfer will be completed when he turns 18."
At the World Cup, Aminu started Ghana's opening two matches against Colombia and the USA but his unconvincing performance saw him relegated to the bench for the last three matches against hosts India, Niger and Mali as the Black Starlets were eliminated in the quarter-finals.