A U.S.-backed push for a future Palestinian state hinges on President Mahmoud Abbas doing what may seem impossible -- getting Hamas Islamists to give up the Gaza Strip and disarm.

Abbas has done little to explain how he expects to achieve such a feat, either through new elections or militarily.

He and Israeli Prime Minister Ehud Olmert launched their peoples' first formal peace talks in seven years this week with the goal of forging a deal next year to create a state in Gaza and the West Bank, together home to 4 million Palestinians.

Olmert has vowed not to carry out any peace deal until Abbas reins in militants, including Palestinian Hamas Islamists who seized control of Gaza in June and have rejected U.S. President George W. Bush's push for peace.

Hamas has vowed to undermine Abbas's talks with Olmert by keeping up its fight against Israel.

His secular Fatah forces having been routed in Gaza, Abbas assured Bush at a conference in Annapolis, Maryland, that he would not engage in dialogue with the Islamist group unless it first gave up control of Gaza.

But Abbas acknowledged: "We do not know what procedures will be used."

Washington likewise has offered no detailed solutions, at least not publicly.

"We are looking for a two-state solution, not a three-state solution. This is not Israel, West Bank and Gaza," White House national security adviser Stephen Hadley said. "The Palestinians in Gaza are going to have to make a choice."

Israel captured both territories in the 1967 Middle East war and pulled out of Gaza in 2005. It regards Gaza as an enemy and regularly launches raids to stop militants' rocket attacks on the Jewish state.

Israel also has repeatedly warned Abbas against any renewed dialogue with Hamas, saying that would torpedo peace moves.

It is unclear whether Abbas has any near-term military options in Gaza despite U.S. efforts to strengthen his security forces.

Israeli officials have hinted at a major incursion against Hamas if rocket attacks against Israel continue. Any international forces would face a hostile reception from Hamas, the group has vowed.

Abbas said he intended to put any final peace deal with Israel to a referendum, seeking public support to weaken Hamas's hold on Gaza. Hamas maintains that Abbas does not have the power to call elections and that any new polls must wait until 2010 under Palestinian law.

"If the Israelis weren't able to suppress them, how will Abbas be able to suppress them?" Zakaria al-Qaq of al-Quds University said of Hamas. "He will not be able to deliver (a state) without Hamas. He has to buy them in and now the price will be very large."

COOPERATION

Hamas, which does not recognize Israel and said on Thursday there was "no place for Jews" in the land that was once British-run Palestine, won Palestinian elections in 2006.

But it struggled to govern after it was shunned by the international community for refusing to denounce violence.

Hamas formed a unity government with Fatah in March but Abbas sacked the administration after the Gaza takeover.

Israel has tightened border restrictions since the takeover by Hamas and the Gaza economy is in virtual meltdown.

While a new Palestinian unity government involving Hamas and Fatah may seem out of the question for now, Western officials say some cooperation with Hamas will be necessary, especially over Gaza border crossings.

Abbas is preparing to put his prime minister, Salam Fayyad, at the helm of a committee to control the crossings in the occupied West Bank, where Abbas's Fatah holds sway, as well as the Gaza Strip, Palestinian officials said.

Diplomats said one option was for Hamas to let Abbas's Presidential Guard resume manning the borders; another was for Hamas to pull its forces back to let in a third party.

Palestinian political analyst Ali Jarbawi predicted Israel and the Palestinians would first focus peace talks on the West Bank. If ordinary Palestinians in Gaza saw the talks yield positive changes for their brethren in the West Bank, they may pressure Hamas to retreat, he said.

Jarbawi said that if Palestinian-Israeli peace talks make headway in the West Bank, he could turn to Arab countries -- possibly led by Saudi Arabia, which brokered the last unity government -- to help mediate a deal with Hamas on Gaza.

Asked how peacemaking could work without Hamas, Tony Blair, an envoy for the Quartet of Middle East mediators, told NBC News that Gazans would eventually have to answer the question: "Do you want to be a part of this peace process or not?"

(Additional reporting by Tabassum Zakaria and Patricia Wilson; Editing by Rebecca Harrison and Howard Goller.)