Hamas politiburo Khaled Mashaal backed away from a six month deadline he set the day before for achieving a Palestinian state or else the militant group would launch a new intifada against Israel.
However, he warned during a television interview aired Sunday that if negotiations were ignored, Palestinians would "carry on their struggle".
Mashaal, who spoke during a taped show on a state-run Egyptian television station, said Hamas would be willing to give negotiations more time if there was a chance to "open a political horizon".
"I said six months, but do you want more than six months? Maybe we can take eight months or a year," Mashaal said, responding to a question from Nabil Shaath, the Palestinian Information Minister and a member of Fatah.
During the interview, the TV show telephoned Shaath who told Mashaal on-air that it was not logical for Palestinians to be talking about an intifada.
But Mashaal also warned: "If the door is sealed and the horizon is closed (for creating a Palestinian state) then we have to look for another choice. We will impose our will on the Zionist enemy and the international community."
"The most important thing is that the Palestinian people will not give up their rights. They will not surrender and will carry on their struggle," the exiled Hamas leader said during the taped program titled "Point of View".
Mashaal on Saturday had said Hamas was willing to allow negotiations with Israel but warned of a new uprising if talks failed to reach a deal for a Palestinian state within six months.
It was the strongest confirmation by Mashaal that the militant group was willing to give Palestinian President Mahmoud Abbas the chance to try to negotiate with Israel, but it also was the first time he set a deadline with a specific threat of a new uprising.
Mashaal's remarks came as a fledging cease-fire between Israel and Palestinian factions took effect early Sunday. Hamas and Fatah publicly backed the truce, and Palestinian officials said Mashaal played a role in speeding up the agreement.
Mashaal - who headed back to Syria Sunday night after spending several days holding talks with Egyptian officials in Cairo - did not mention the ceasefire during the interview.
It was unclear when the program was taped.
Progress also was being made regarding a prisoner exchange with Israel for the release of captured Israeli soldier Gilad Shalit, Mashaal said. "Now Israel is forced to move on the swap deal. There is progress, but it needs more time and effort," he said.
Earlier Sunday, Mashaal's deputy Moussa Abu Marzouk said he expected Israel and Hamas would start exchanging prisoners soon, but said efforts to free Cpl. Gilad Shalit were not linked to forming a new Palestinian unity government.
Addressing this issue, Mashaal said: "The Palestinian-Palestinian dialogue is still ongoing and we will overcome the problems. We need some time but we are walking in the right direction."