After more than 200 fatalities, with scores more wounded, Hamas' politburo chief issued a pointedly aggressive statement.
"I call upon you (Palestinians) to carry out a third intifada," Mashaal, who lives in exile in Damascus, told Al-Jazeera television in an interview.
Mashaal pledged Hamas would respond to Israel's operation in Gaza against the Islamist group. "The time when you were the ones to control the Israeli-Palestinian conflict is over," he said, and vowed that "Gaza will soon be liberated" despite Israel's military superiority.
He called for a "military intifada against the Zionist enemy", as well as "a peaceful intifada internally", an apparent reference to Hamas' power struggle with Western-backed Palestinian President Mahmoud Abbas.
Mashaal added that Hamas "would defend itself. The military wing understands what is required of it. It must shoulder the responsibility and coordinate its moves to respond to this aggression."
He said that he was not promising major surprises from Hamas' armed cells because of the ongoing siege on Gaza.
Meanwhile Hamas Prime Minister Ismail Haniyeh declared on Saturday that Gaza would never cave to Israeli pressure, no matter how great. "We will not leave our land, we will not raise white flags and we
kneel only before Allah," he said.
"There is blood everywhere, there are wounded and martyrs in every house and in every street. Gaza today was decorated by blood ... There can be more martyrs and there can be more wounded but Gaza will never be broken and will never surrender," Haniyeh said.
In a statement broadcast by the Hamas-owned Gaza-based television channel, Al-Aqsa, Haniyeh said: "Palestine has never witnessed an uglier massacre."