Ansu Fati has been called into the Spain Under-21 squad, just 24 hours after being granted clearance to play for his adopted country.

Fati was added to the party to face Montenegro on Tuesday after Barcelona team-mate Carles Perez was forced to withdraw through injury.

It continues a remarkable rise to prominence for the 16-year-old, who became Barca's youngest LaLiga goalscorer when he found the net against Osasuna in August.

Born in Guinea-Bissau, Fati also had the option to represent Portugal at international level, but was granted Spanish citizenship and chose to play for La Roja.

The Royal Spanish Football Federation confirmed on Thursday that FIFA had granted Fati permission to represent Spain at international level.

Spain's youth team sporting director Francisco Hernandez suggested Fati could be fast-tracked into the senior squad after opting to leave him out of the squad for the Under-17 World Cup in Brazil.

"We have taken the decision not to include him in this [World Cup] squad," Hernandez said.

"This was following a wider sporting review in that we consider him in a better position to play with an older category and for that to be the case, he cannot come to the Under-17 World Cup.

"We want him to star for the senior team as soon as possible."

Spain senior coach Robert Moreno said Fati was on his preliminary list for the current international break.

"We thought he could do well," he said. "He was on the preliminary list, we value him, there were a number of events that have been going on, bureaucratic issues after he was injured and we could not summon him.

"Allow me for this exception when talking about someone who is not on the list, but he was a special case that had to be treated in an honest way."