The agent of Anthony Martial has taken aim at Manchester United over their contract negotiations.

United have taken the option to extend Martial's current contract by one year, tying the Frenchman to Old Trafford until 2020. But talks over a new five-year contract have so far proved fruitless.

It is understood Martial is keen to remain at Old Trafford but his agent Philippe Lamboley has now revealed the club have much to do if they want to keep the player in the long-term.

“I am very pessimistic about discussions going positively," Lamboley told RMC Sport.

“They've already made several offers that come nowhere near to what we expect."