Anthony Joshua and Deontay Wilder's hotly-anticipated unifcation fight could be put on hold after the WBA ordered him to sign for a mandatory title defence against Alexander Povetkin "within 24 hours".

WBA president Gilberto Mendoza said: "Today the WBA requested an answer from Anthony Joshua's team regarding his fight with the mandatory challenger Alexander Povetkin.

WBC champion Wilder hasn't returned his contract to fight with Joshua for all the world heavyweight belts - and the WBA have now ordered the British star to fight against Povetkin to fulfil his title obligations.

Mendoza said, "The WBA have allowed over a month extension to negotiations with Povetkin and also ongoing discussions with Deontay Wilder... It appears the Wilder team have not returned the contract for the fight and therefore we are requesting a date for the Joshua versus Povetkin fight with immediate effect."

AJ's camp have yet to respond to the request.