A statement released by the radical Islamist movement said: “These statements do not reflect the official positions of the movement and its adopted and consistent policies.
Hamas added that it had previously condemned attacks on Jews in their places of worship.
Hammad was speaking at a “March of Return” protest against Israel by the Gaza border.
He told demonstrators in Gaza that new factories had been opened to manufacture explosive belts and that each protester could take one and cross the border to Israel in order to kill Jews.
The UN’s special coordinator for the Middle East peace process, Nickolay Mladenov, condemned the remarks.
“A dangerous, repugnant and inciteful statement! It must to be clearly condemned by ALL. There can be no complacency with such rhetoric. Ever!” Mladenov tweeted on Monday.
Hamas leader Ahmed Yousef sent a letter to Hammad criticizing his choice of words.
“I understand your anger at Israeli occupation crimes against our people, but the language of explosive belts is not the language of politicians, and talking about killing Jews is a violation of religion and morals and even contrary to what is stated in Hamas political documents,” he said.
(Edited by Emmanuel Yashim)