President Obama will embark on his deepest foray into Middle East peacemaking next month when he hosts Israeli and Palestinian leaders in a bid to achieve what his predecessors could not: a deal to establish a Palestinian state alongside Israel and end the two sides' bitter conflict.

Secretary of State Hillary Rodham Clinton announced Friday that Israeli Prime Minister Binyamin Netanyahu and Palestinian President Mahmoud Abbas are expected in Washington on Sept. 2 for what will be the first face-to-face negotiations between the sides in two years. Clinton said she thinks a deal could be reached within a year.

The announcement marked a small victory for Obama, who had pledged to address the conflict early in his term but faces a daunting challenge in pulling off an agreement.

"Without a doubt, we will hit more obstacles," Clinton said. "The enemies of peace will keep trying to defeat us and to derail these talks. But I ask the parties to persevere."

The first big test for the renewed peace process will probably be the scheduled expiration Sept. 26 of a 10-month freeze by Israel on new settlement construction in the West Bank, which it has occupied since 1967. Israel has sought to ensure that the United States will not call openly for a continuation of the freeze.

In a nod to those concerns, Clinton said talks "should take place without preconditions." But Middle East envoy George J. Mitchell hinted that Netanyahu would be under pressure to extend the freeze, saying that both sides should "refrain from taking any steps that are not conducive to making progress." Mitchell has been conducting shuttle diplomacy between the antagonists for months.

Saeb Erekat, the chief Palestinian negotiator, said it is vital the moratorium be continued.

"The non-extension of the moratorium on settlements will mean that we will not have negotiations. It's as simple as this," Erekat told CNN. The Palestinians see the West Bank as the main part of their future homeland, along with the Gaza Strip.

Shlomo Brom, a former Israeli peace negotiator, said the U.S. government had pressed to launch talks soon "to prevent a crisis in September" when the freeze expires.

He described the outlook for the negotiations as grim, however, saying that Netanyahu will not offer as many concessions to the Palestinians as former Israeli premiers did.

Another difficulty is the split between the West Bank and Gaza. The latter is run by Abbas's rival, the Islamic militant group Hamas, which the United States and others label a terrorist group.

Many say that the split undercuts Abbas's ability to negotiate a comprehensive peace deal. In the run-up to Friday's announcement, rocket fire from Gaza targeting Israel has continued sporadically. Hamas on Friday rejected the idea of new peace talks.