Manchester United said on Thursday that they are "in danger" of breaching the Premier League's Profit and Sustainability Rules (PSR).

The club made the admission in a letter sent to fans groups in response to concerns over rising ticket prices. United have reported losses before tax of 312.9 million over the last three years with the precarious financial position so far, preventing head coach Ruben Amorim from making any signings in the January transfer window.

"We are currently making a significant loss each year totalling over 300 million in the past three years," the letter issued by the club said. "This is not sustainable and if we do not act now we are in danger of failing to comply with PSR/FFP (Financial Fair Play) requirements in future years and significantly impacting our ability to compete on the pitch.

"We will get back to a cash positive position as soon as possible and we will have to make some difficult choices to get there."

Premier League clubs in breach of PSR rules can be hit with fines and points deductions. New co-owner Sir Jim Ratcliffe has implemented wide-ranging cost-cutting measures since taking over in February including making 250 club staff redundant in the summer.

Sources have told ESPN that United's tight finances mean they are open to offers for any senior player in January. That includes academy graduate Alejandro Garnacho.

Although the club does not want the youngster to depart, they may be forced into negotiations with either Chelsea or Napoli before the deadline.