​Arsenal have confirmed the signing of highly-rated defender William Saliba from Saint-Etienne on a long-term deal, before immediately sending the player back to the Ligue 1 side on loan for the 2019/20 season.

The Gunners had been locked in negotiations over a deal for the 18-year-old, with the structure of payments and Saint-Etienne's demands that the player be loaned back to the club making an agreement hard to reach.

​​A solution has finally been found, however, with ​Arsenal confirming on their official website that Saliba has put pen to paper on a long-term contract - thought to be five years long.

In a ​short statement, head coach Unai Emery expressed his delight at securing Saliba's services, saying: “We’re delighted William is joining us. Many teams wanted him but he decided he wanted to come to us and be part of our future. 

"He will stay in France next season for more experience and then we look forward to him joining our group.”

Emery's side fought off late competition from north London rivals ​Tottenham for the Frenchman's signature, but ​Arsenal have secured a move for the player who broke into Les Verts' first team last season, making 16 appearances in Ligue 1.

The fee for Saliba is rumoured to be around the €30m mark, with Emery's confirmation that he will head back to France an indication that the club are planning for the long-term, not just the immediate future.

Earlier, Arsenal announced they ​had completed the signing of Real Madrid midfielder Dani Ceballos - stabilising the club's activity in the transfer window after weeks of setbacks involving numerous other targets.