Morocco boss Herve Renard has held talks with the 18-year-old's representatives in recent weeks in a bid to convince the youngster he should turn his back on Spain and play for the country of his grandmother.
Renard has offered assurances that the youngster, who made his full City debut on Tuesday, would be part of his World Cup squad.
Brahim, full name Brahim Abdelkader Diaz, was born in Malaga. His mother is also from Malaga while his father is from Melilla, a Spanish city in the north of Africa on the border with Morocco.
The City playmaker has already represented Spain at various youth levels and sources close to him have told Goal that he considers himself to be Spanish and is determined to break into the senior side.
It is understood he may consider switching allegiances much later in his career if he fails to make the grade for Spain, but he is confident he has what it takes to get into the squad in the coming years.
The African nation are attempting to recruit foreign-born players ahead of the tournament in Russia. Real Madrid defender Achraf, born in the Spanish capital, switched allegiances in 2016 and, after making a handful of appearances for the country's youth sides, made his full debut in the same year.
Morocco have also tried to get Alaves forward Munir, also born in Madrid, to join them. The 22-year-old, on loan from Barcelona, has already made a competitive appearance for Spain, however, and will not be allowed to jump ship.