Tyson Fury has urged Anthony Joshua to “give British fans what they want” and sign a contract for a heavyweight world-title fight in December.
WBC champion Fury, had given fellow Briton Joshua, an ultimatum to sign by Monday, but said on social media he has extended the deadline to Thursday.
Joshua’s promoter Eddie Hearn says he is “baffled” by Fury’s latest demands.
Joshua’s team have already verbally accepted Fury’s offer of a 60-40 purse split for a fight on December 3.
Last month, Joshua failed to regain the WBA (Super), WBO and IBF belts in a rematch with Oleksandr Usyk, losing on a split decision.
Fury’s promoter Frank Warren says he does not know what is preventing the contract being signed.
His last fight was a sixth-round knockout victory over fellow Briton Dillian Whyte in April.