GAZA CITY, Gaza Strip -- Palestinian Prime Minister Ahmed Qureia joined rival Palestinian groups in a call for unity Saturday, hoping they could work together to ensure calm and keep the Gaza Strip from plunging into chaos if Yasser Arafat dies.

But in a sign of the challenges ahead, the Islamic militant group Hamas issued what it called an "urgent demand" for a formal role in Palestinian decision making in the post-Arafat era.

"This time is very sensitive. It's a historic time. There is no space for any unilateral decisions," Hamas spokesman Sami Abu Zuhri said, alluding to Fatah, Arafat's core organization. "Everyone now is calling for the formation of a united Palestinian leadership. This is a demand of our people."

Abu Zuhri called for a joint leadership to serve in an advisory role during a "transitional period until we have an election in which our people will be able to choose their representatives."

Hamas, which boycotted the only Palestinian general election in 1996, has recently agitated for a role in the Palestinian leadership. New national elections have not been set, though a voter registration drive was recently concluded, with Hamas taking part.

As Arafat's receives emergency medical treatment in France, Qureia and other Palestinian officials have held a flurry of meetings with political and security officials trying to ensure calm, especially in Gaza, where rival groups and security officials have fought in the streets, jockeying for power before Israel's planned withdrawal from the coastal strip next year.

Traveling in a motorcade that included eight vehicles of security forces, Qureia met four hours Saturday with representatives of 13 factions -- including Hamas and Islamic Jihad -- as well as security chiefs, lawmakers and Fatah officials. Such a broad gathering is extremely rare.

After the meeting, Qureia said the security commanders were committed to a joint plan "to ensure security and order." The political factions said they would work together with the Palestinian government "to reach a national program and a national plan and to achieve a political partnership."

Nabil Abu Rdeneh, a senior aid to Arafat, announced that Arafat was not in a coma but remained in intensive care Saturday after undergoing more tests at a hospital near Paris. He refused to say whether he saw Arafat personally, and did not specify the nature of the new medical tests.

Qureia declared himself encouraged by the meeting and said the groups would meet again to discuss the possibility of a cease-fire and "restoring law and order and security control." He returned to the West Bank after the meetings.

Qureia has tried to persuade militants to accept a cease-fire in hopes of restarting peace talks with Israel, but Abu Zuhri ruled that out.

"The resistance continues and will stop only if the occupation ends," he said. Hamas refuses to accept Israel's right to exist.

Hamas' representative in Lebanon, Osama Hamdan, said the militant group would not stop fighting, even if Israel withdraws from Gaza. Hamas also would reject any Arafat successor it feels has Israel's backing.

"We will not accept a leadership that is brought by Israeli tanks," he told a rally in south Beirut on Saturday. "Our sole legitimate choice is resistance until we regain our rights."

All the groups at the Gaza talks -- including Hamas -- called for unity Saturday, and it was unclear if comments from Abu Zuhri and other Hamas leaders portend the power struggle widely expected when Arafat dies.

"We should work together, all the factions and all the Palestinian people together, to protect our unity and to protect our homelands," said Abdel Aziz Shaheen, a top Fatah official in Gaza.

Parliament Speaker Rauhi Fattouh, a key figure in any transition, accompanied Qureia to Gaza. Fattouh would become president of the Palestinian Authority for 60 days until new elections.

Palestinian officials worry that Fattouh, a bland politician with no independent power base, may not be capable of assuming even that caretaker job.

Palestinian officials said they were looking a means to block Fattouh from assuming office, perhaps by delegating power to Qureia and former Prime Minister Mahmoud Abbas, Arafat's deputy in the Palestine Liberation Organization.

In what appears to be an emerging joint leadership, Abbas would handle diplomacy, while Qureia would deal with the daily affairs of governing.