"We give the international community six months for real political horizons... There is a historic opportunity for a Palestinian state within 1967 borders."
Meshaal had been meeting Egyptian officials on the formation of a Palestinian unity government by Hamas and its rival, Fatah.
Discussing Meshaal's talk about a third intifada, Walid Batrawi, Al Jazeera's Ramallah correspondent, said Palestinians are unlikely to back a new uprising.
"On the ground Palestinians have suffered much. Palestinians are looking for a just peace not going to a third intifada when they have no resources for resistance," he said.
"If our demands are not met, the Palestinian people will close all political files and launch a third intifada"
Khaled Meshaal, Hamas leader
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Meshaal was upbeat on the prospects for an agreement on a government with Fatah saying that "good strides" had been made, but "more time" would be needed.
The two sides also discussed a potential prisoner-swap deal with Israel over the release of a captured Israeli soldier.
Hamas has said it wants the release of more than 1,000 prisoners in return for the soldier.
Israel has occupied the West Bank and Gaza since 1967.