Heavyweight world champion Oleksandr Usyk has been ordered by the WBO to begin negotiations with Joseph Parker for a mandatory title defence.

Parker, 33, retained his interim WBO title in February with a second-round knockout win against Martin Bakole.

Ukrainian Usyk is the WBC, WBA (Super) and WBO heavyweight champion thanks to his second successive victory against Tyson Fury in December.

Usyk and Parker have 30 days to find an agreement or the WBO will order purse bid proceedings.

More to follow.