Musannaf Ibn Abi Shayba 35:409

Ubayd Allah ibn Musa narrated to us, from Usama ibn Zayd, from al-Zuhri, from Anas, who said: When the day of Uhud arrived, the Prophet (peace be upon him) passed by Hamza, and he had been mutilated and disfigured. He said: "Were it not that Safiyya would be distressed, I would have left him until Allah gathered him from the bellies of the beasts and the birds." He did not perform the funeral prayer over any of the martyrs, and he said: "I am a witness over you today." And they mentioned that Abu Hanifa said: "The funeral prayer is performed over the martyr."