It is narrated from Sayyiduna Ali (may Allah be pleased with him): "The mu'adhdhin has more right over the adhan, and the imam has more right over the iqamah."
It has also been narrated from Sharik, from al-A'mash, from Abu Salih, from Abu Hurayrah as a saying of the Prophet (marfu'), but that is not mahfuz (preserved).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2279