MANCHESTER, United Kingdom (AFP) - Manchester United on Wednesday completed the signing of Swedish international centre-back Victor Lindelof from Benfica for a fee believed to be £31 million (S$54 million), the English Premier League side announced.

"I am thrilled to be joining Manchester United," said the 22-year-old after penning a four-year deal.

"I have enjoyed my time at Benfica enormously and I have learned a lot there. But I'm looking forward to playing in the Premier League at Old Trafford and for Jose Mourinho."

Lindelof joined Benfica from home-town club Vasteras SK in 2012 and won three Portuguese league titles and two Portuguese Cups during his time in Lisbon.

Lindelof is the second centre-back signed by United manager Mourinho following last year's capture of Ivory Coast international Eric Bailly from Villarreal.

Mourinho also has England pair Chris Smalling and Phil Jones at his disposal, along with Argentina international Marcos Rojo, while Dutch utility man Daley Blind has slotted into central defence on occasion.

"Victor is a very talented young player, who has a great future ahead of him at United," said Mourinho on Wednesday.

"Our season last year showed us that we need options and quality to add depth to the squad and Victor is the first to join us this summer. I know that our fantastic group of players will welcome him as one of us."

Lindelof is United's first new signing of the summer as they build up towards a Champions League campaign next season.

They are also in the market for a striker, having included Zlatan Ibrahimovic, currently sidelined by a serious knee injury, on their list of players to be released.

Real Madrid striker Alvaro Morata is one name linked with a move to Old Trafford.

His agent said earlier this week that United had lodged a "very important offer" with the Spanish giants to try to bring him to Manchester.