Barcelona's player Lamine Yamal. AP
Regragui emphasized the importance of respecting Yamal's decision and avoiding unnecessary pressure on the player.
During a news conference in Morocco, Regragui announced the list for Morocco's September camp, which notably did not include Yamal, who holds Spanish nationality.
The 16-year-old, born in Spain to a Moroccan father and an Equatorial Guinean mother, is yet to determine the country he will represent.
Reports have suggested that he may feature in the list of players announced by Spain coach Luis de la Fuente on Friday.
"The essential thing is that the player, as well as his father, are Moroccans." Regragui told a news conference in Morocco on Thursday.
"There is no need to put pressure on the player and his decisions. We will not get ahead of events. We will see tomorrow what his choice will be."
Yamal, who has displayed impressive skills during his recent games with FC Barcelona, is considered one of the most promising prospects in Spanish football.
Morocco made a mark in the last World Cup, securing a remarkable fourth-place finish in Qatar and becoming the first African country to reach the World Cup semi-finals.
They defeated Spain in the round of 16 of the competition through a penalty shootout after a goalless draw in regular time.
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