Birmingham have issued a statement confirming they are under transfer embargo.
It had been reported this month that the club had the sanction imposed on them by the EFL for failing to convince the governing body that they were working within Financial Fair Play guidelines.
Blues boss Garry Monk has been frustrated by a lack of new signings this summer, with just Danish defender Kristian Pedersen arriving at St Andrew’s.
Birmingham have now addressed the situation for the first time with a club statement, which read: “The club has spent several months working diligently to satisfy the EFL.
“Unfortunately and disappointingly the EFL are currently refusing to allow us to make additions which would enable us to strengthen the manager’s squad.
“We are hopeful that a satisfactory agreement can be reached with the EFL as soon as possible to help ensure our continued competitiveness in the Championship.
“We fully understand supporters’ frustrations over this issue in the wake of recent speculation and rumour. We share those frustrations.
“The club asks supporters to maintain the fabulous and passionate backing they have given to Garry Monk and the team since the manager’s appointment – it is hugely appreciated and when we have that togetherness and strength in numbers it can make a big difference.
“The board of directors are ambitious and are committed to improvement and bringing success to the club, in all aspects on and off the field.
“And supporters can rest assured that we are doing everything in our power to address this current situation.
“The club will make no further comment. We thank you for your understanding.”