Six-time Ballon d'Or winner Lionel Messi told Barcelona FC he wants to leave—on a free transfer—in a bombshell fax on Tuesday that is expected to spark a legal battle over a buy-out clause worth hundreds of millions of dollars. Signalling the end of an era at Barcelona, where Messi, 33, is the record scorer and has won four Champions League titles, the disgruntled Argentine wants to terminate his contract unilaterally by triggering a release clause, a source told AFP.

But the club hinted that a legal battle could be coming and said it won't automatically grant the Argentina great his wishes. The dispute centres around a clause in Messi's contract. Barcelona said the document sent by Messi referenced a clause allowing him to leave for free at the end of the season. However, the club said the deadline for triggering that clause expired in June and that it would seek legal advice.