It is narrated from Sayyiduna Khawt bin Abd al-Uzza (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) ordered that bells be cut off.
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4174
It is narrated from Sayyiduna Khawt bin Abd al-Uzza (may Allah be pleased with him); he said: A caravan of the tribe of Mudar passed by with a bell in it, and the Prophet (peace and blessings be upon him) said: "The angels do not come near a caravan in which there is a bell."
Hadith Referenceالمعجم الكبير للطبراني / باب الخاء / 4175