Is it permissible to say: "Allahumma salli 'ala Sayyidina Muhammadin wa 'ala alihi wa sahbihi wa sallim. Allahu Akbar, Allahu Akbar" before the establishment of the prayer (Iqamah)?

It has not been authentically reported from the Prophet, peace and blessings be upon him, that he commanded or approved the saying: "O Allah, send prayers upon our Master Muhammad, and upon his family and companions, and grant them peace" before the Iqamah. This statement is an innovation and a bid'ah (religious innovation), and every bid'ah is misguidance, and "whoever introduces into this matter of ours that which is not from it, it is rejected." Muezzins should be alerted that this action could be a cause for their deeds to be rejected and not accepted by Allah.