Paul Pogba
Manchester United's Pogba challenges Stoke City's Wilson during their English Premier League match in Manchester.

Manchester United face a battle to retain highly-rated teenager Paul Pogba after his agent revealed the two parties are yet to agree terms on a contract extension for the Frenchman.

Pogba, 18, has been repeatedly linked with a move abroad as talks over a new deal continue to flounder. Manchester City and Inter Milan have both been mentioned as possible suitors in the summer and the latest comments from Pogba's agent will only have fuelled talk of a possible exit.

The midfielder's agent, Mino Raiola, admitted Pogba's future at Old Trafford was "precarious" after he was left out of the squad for Manchester United's second leg Europa League tie against Ajax.

Pogba, who is out of contract at Manchester United in the summer, was reportedly excluded from first-team training last Friday and Raiola acknowledged the youngster faces an uncertain future at the club.

"It is a precarious situation. It is difficult," Raiola told ESPN Soccernet. "United want him. It is up to the boy to make some decisions."

Earlier this month, Manchester United manager Sir Alex Ferguson revealed his frustration over Pogba's contract talks but said Rio Ferdinand could prove crucial in convincing the midfielder to remain at Old Trafford past the end of the season.

"Rio has become an important figure at the club. He is good with the players. He is good with the young players," Ferguson told the Manchester Evening News.

"At the moment, he is working hard on the boy Pogba and talking to him. The young boy is unsure but Rio is well regarded."