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Borussia Dortmund have confirmed the signing of teenage Barcelona midfielder Sergio Gomez on a "long-term contract" for a fee reported to be in the region of €3m (£2.6m).
Gomez, 17, was part of the Spain squad that reached the final of the Under-17 World Cup in India last year.
He becomes Dortmund's second signing of the January transfer window following the arrival of Swiss defender Manuel Akanji from Basel.
"Sergio Gomez is undoubtedly one of the strongest players of his age in the world," Dortmund sporting director Michael Zorc said in a statement.
"We have been interested in him for some time now and we are happy that he has decided to come to Borussia Dortmund despite offers from many top European clubs.
"Sergio will be training directly with the senior squad and gaining match practice in our Under-19s by the summer."
Gomez made his debut for Barcelona's B team in a 1-1 draw with Real Zaragoza earlier this month. He was voted the second best player at last year's Under-17 World Cup after scoring four goals in seven games for Spain.
The 17-year-old said he is grateful to have the opportunity to play for "one of Europe's biggest clubs".
"I just want to give it my all from my first training onwards on Monday," the young midfielder said.
"I feel like I can contribute a lot to this club and I can play in various positions across the attack, but first of all, I need to adapt to the coach's philosophy."
Meanwhile, Dortmund remain on the hunt for a replacement for Pierre-Emerick Aubameyang, who looks set to complete a £55m transfer to Arsenal on deadline day.
The Bundesliga side have fixed their sights on Chelsea striker Michy Batshuayi, who is keen to leave Stamford Bridge to secure more playing time during a World Cup year.
Dortmund are also interested in Arsenal striker Olivier Giroud, but the Frenchman is understood to have rejected the move as he wants to remain in London.