The reports also claimed that Blues had offered to sell the player to Osasuna if they matched the fee they paid for the player and that FIFA were to begin an investigation into Blues new signing.
“We think it’s inappropriate for Osasuna to make the statement they did,” Sullivan told the Birmingham Evening Mail.
“We will make no comment on what they have claimed.
“What we will say is that it’s in the hands of FIFA and we welcome any investigation as the whole thing is a mess.
“Hopefully the matter will be resolved as soon as possible for the player’s sake, our sake and Osasuna’s sake.
“As far as we’re concerned, we paid fully for Luciano and hold his registration until such time it can be proved to the contrary.
“Whether an agent or lawyer signed an agreement with Osasuna purporting to represent the player we don’t know.
“What we do know is that Luciano is with us, he’s a Birmingham City player and he’s as keen as mustard to do well in England.”