Is it permissible for the muezzin of the mosque to make supplications on the loudspeaker after every Adhan?

Supplicating after the adhan is a Sunnah and a likely time for supplications to be answered, based on the hadith: "The supplication between the adhan and the iqamah is not rejected." However, raising one's voice with it through loudspeakers is an innovated bid'ah. The act itself is a Sunnah, but the manner of its performance is an innovation. العلامة Ibn Hajar issued a fatwa stating that sending blessings and peace upon the Prophet after the adhan in the manner of the mu'adhdhins is an innovation. Sheikh Ibn 'Uthaymin was asked about this and replied that if the mu'adhdhin recites this supplication in a loud voice through a loudspeaker, it becomes as if it is part of the adhan, and this was not known during the time of the Prophet, peace be upon him, or the Rightly Guided Caliphs. Thus, it is among the forbidden innovations.