Borussia Dortmund have signed Manuel Akanji from FC Basel, with the Bundesliga club announcing that the Swiss international defender has signed a deal until June 2022.

Neither club has revealed the fee paid by Dortmund for the player, but German media report that the eight-time German champions paid around 21.5 million euros ($26.4 million).

"Manuel's performances put him on the radar of a number of top European clubs, and we're delighted that he's chosen to join us," said Borussia Dortmund's sporting director Michael Zorc on the club's website.

"He has already demonstrated at international and Champions League level that he can play at the highest level in Europe. Nonetheless, we still see him as a defender who has potential for further development."

Akanji, 22, has four international caps for Switzerland and played in all six of Basel's Champions League group games as they qualified for the knockout stages alongside Manchester United, after winning the domestic league and cup double last season.

"The discussions I've had with those responsible at Borussia Dortmund made me feel comfortable. In that respect it was a decision of the heart," said Akanji.

"I've always enjoyed the football they play in Dortmund."

Dortmund are currently fourth in the Bundesliga, 15 points behind leaders Bayern Munich and on the heels of Schalke and Leipzig.