Championship club Nottingham Forest are embroiled in a legal battle with former owner Fawaz Al Hasawi.
The Kuwaiti businessman, whose ownership of the Reds ended last May, was sued by the club in December over money they claim is owed following the sale to Evangelos Marinakis.
Al Hasawi has, in turn, responded by launching his own proceedings against Forest, stating that he believes he is owed around £4.2m in unsecured interest free loans.
A spokesman for the club's solicitors, Browne & Jacobson LLP, is quoted by The Telegraph as saying: "We can confirm that Nottingham Forest has commenced proceedings against Mr Al Hasawi and a related party claiming various sums that have become due and owing since the completion of the sale of the club in May 2017.
"Mr Al Hasawi has issued proceedings against the club in response. It would not be appropriate for us or the club to comment further on these proceedings until they are resolved."
Marinakis, who is also owner of Greek club Olympiacos, is not involved in the proceedings, which are being contested between Al Hasawi and the club.