"The enemy has given obscure and incomplete answers through Egypt that do not reach the level of lifting the siege," Mashaal told a rally in Damascus to celebrate the "victory" in Israel's 22-day military operation in Gaza that left more than 1300 Palestinian killed and some 5000 wounded.
"The enemy has given no guarantee and we will not accept any truce until after we get our demands done," he added to the applause of thousands of excited audience.
Damascus-based Palestinian factions attended the gathering, organized by Hamas.
"We thank all those who helped us, and we say to those who didn't - God will settle accounts with you," Mashaal said, thanking Syria, Iran, Qatar, Sudan, and Turkey.
Israel imposed a heavy blockade on the densely-populated Gaza Strip after Hamas seized it in June 2007 and ousted Palestinian President Mahmoud Abbas' Fatah group.
The Gaza war ended on January 18 after unilateral ceasefires by both sides.
Egypt has been trying to get Hamas to agree to a lasting deal that would end Palestinian arms smuggling into Gaza, a key Israeli demand, and to re-open the coastal enclave's border crossing, one of Hamas' key demands.
Hamas officials are due to return to Cairo on Saturday to give a final reply to proposals to reach an 18-month truce with Israel following its offensive in Gaza, which was halted last month when the two sides declared separate ceasefires.
"Israel cannot dictate us conditions for a truce after it lost the war in Gaza which strengthened our people's trust in resistance as the path to liberation. Nothing will give us back our territory and restore our Jerusalem but resistance," Mashaal said.
Head of Islamic Jihad Ramadan Shallah said Israel lost the war as it couldn't neutralize the rocket arsenal in the territory and break the will of its population.
"We have managed to prevent our enemy from accomplishing its goals," Shallah said. "It was a victory for the will to live, a win for freedom," he said.