JERUSALEM — JERUSALEM -- In a bold, unexpected challenge to the militant group Hamas, the Palestinian president, Mahmoud Abbas, announced yesterday that he would hold a national referendum calling for a Palestinian state alongside Israel based on its 1967 borders, unless Hamas agreed to those negotiating terms within the next 10 days.
The ultimatum caught Hamas, Israel and the United States by surprise, and raised the stakes in the power struggle between Abbas' Fatah Party, which favors pursuing negotiations with Israel, and Hamas, which controls the Palestinian Authority and refuses to recognize Israel or to renounce violence.
"All the Palestinians, from Hamas to the Communists, all of us agree we want a Palestinian state on the 1967 borders," Abbas said at the opening session of a two-day conference of Palestinian leaders. "This is what we have; we cannot talk about dreams."
Abbas said the referendum would offer voters a five-page plan developed this year by prominent prisoners from Fatah and Hamas being held by Israel. Those prisoners include Marwan Barghouti, a Fatah leader, who is credited as the main author of the prisoners' proposal. The document calls for a Palestinian state in the West Bank, Gaza and East Jerusalem, the areas Israel captured in the 1967 Arab-Israeli war.
"We must rise to the level of responsibility," Abbas said. "If within 10 days you don't reach results through dialogue, I will take the prisoners' document to a popular referendum." He said the vote would take place within 40 days.
Some Hamas officials took care not to reject Abbas' plan outright, but his proposal is radically different from Hamas' own program.
Prime Minister Ismail Haniyeh, a leader of Hamas, hinted he might challenge Abbas' authority to order a referendum. "We will study how the call for a referendum is compatible with the law, the constitution and politics," he said.
Earlier, he told the conference that Hamas would not soften its refusal to recognize Israel, or give up its claim to all its territory.
"I want to assure here, and make it clear for all parties, that the Palestinian government and the Palestinian people will not make any compromise that harms the Palestinian goals and rights," Haniyeh said, before Abbas' speech.
Abbas insisted that Hamas must change its policies or face further isolation.
"The Arab countries are waiting for this realistic position, to work in harmony, to push the Palestinian cause ahead," Abbas said. "They cannot do anything for the Palestinian cause if the [Palestinians] are rejecting everything."
After his speech, Abbas said the Palestinians needed to quickly agree how to resolve conflicts between Hamas and Fatah, and how to deal with Israel, because Palestinians could not wait indefinitely for a secure peace.
"The situation is getting more dangerous," he said. "The whole nation is in danger. We can't wait for the rest of our lives."
A referendum could help relieve the economic and political crisis created by Hamas' hard-line positions. If the peace plan were approved in a referendum, Hamas might feel itself bound by the vote but without being seen to be bending on its own to international pressure.
A referendum would also apply pressure on Israel to restart peace talks and complicate Israeli Prime Minister Ehud Olmert's proposal to decide Israel's final borders unilaterally.
Israeli officials said the terms proposed by Abbas were not necessarily an acceptable basis for talks. A return to the 1967 borders would require Israel to withdraw from all of the West Bank and East Jerusalem, actions not endorsed by Olmert, his centrist Kadima party or its partners in the coalition government.
Israel's Channel Two television, meanwhile, reported that Olmert recently approved supplying Abbas' presidential guards with weapons and ammunition, apparently because of growing concerns about threats to Abbas' life.
Opinion polls in the West Bank and Gaza Strip suggest that the prisoners' agreement would be approved by a substantial majority in a referendum. A survey released this week by Near East Consulting in Ramallah found 80 percent of those poll supported the plan.
Support was higher among Fatah supporters (87 percent) than among Hamas supporters (68 percent) and was also higher in the West Bank (85 percent) than the Gaza Strip (72 percent).
The document includes calls for:
Establishment of a Palestinian state.
The right of Palestinian refugees to return to Israel, a demand Israel has generally found unacceptable in the past.
Continued resistance to the Israeli occupation of the West Bank.
Release of all Palestinian prisoners held by Israel.
Peace negotiations with Israel overseen by Abbas.
Some Hamas figures expressed cautious support for a referendum and the terms of the prisoners' document. The parliament's speaker, Abdel Aziz Duaik of Hamas, said: "Returning to the people is one of the most important principles in democracy."
Israeli Justice Minister Haim Ramon said the referendum was "worthy of examination." But another Cabinet minister, Interior Minister Ronnie Bar-On, said that as long as Hamas did not recognize Israel and renounce violence, Abbas' idea "is like playing checkers with himself."
Analysts reacted cautiously to the proposal, which had been discussed in recent months, noting that it is unlikely to restart serious peace talks.
"If there is a referendum and there is a majority accepting that document, maybe Hamas will go along," said Ali Jirbawi, a professor of political science at Birzeit University. "But it won't consider that it has to recognize Israel. It's not a formal recognition of Israel."
More important, Jirbawi said, the proposal doesn't address the escalating tensions between Hamas and Fatah regarding control of the Palestinian security forces. "It is a good move, but I'm not sure if it is going to fly," he said. "I'm still not sure if it is going to end the internal conflict."