The World Boxing Organization announced Tuesday that it would not authorize a proposed unification bout in Texas on May 9 between Japan's WBO bantamweight champion Tomoki Kameda and Britain's WBA champion Jamie McDonell.

The WBO said in a letter emailed to Kameda and posted on its official website that it would not allow the bout to go ahead, since Juan Carlos Payano of the Dominican Republic is the WBA super champion in the bantamweight division and thus ranked higher than McDonnell.

"The WBO World Championship Committee will not authorize your proposed bout with Jamie McDonnell as a unification contest, as it our position not to recognize the "secondary titlists" of organisms that opt to have more than one champion per division — as is the case with the WBA, which has Juan Carlos Payano as its so-called "super champion" in the bantamweight division and Yonfrez Parejo as its "interim" titleholder," the letter read.

"Simply put, the WBO only recognizes the "highest" titleholder of other sanctioning organisms as legitimate champion for unification purposes (in this case Payano)."

"In addition to this, the WBO World Championship Committee may only sanction contenders to the WBO World Championship title that are rated within the top 15 of the WBO. In this case, McDonnell does not meet the criteria of the WBO Ratings Committee and is not rated."