US Secretary of State Condoleezza Rice is returning to the Middle East to move ahead preparations for an international conference on Palestinian statehood.
Ms Rice will meet Palestinian and Israeli leaders to agree a framework for the summit, which is expected to take place in the US in late November.
During her visit last month, she urged both sides to draft a document laying the basis for serious negotiations.
Ms Rice is fresh from difficult talks in Russia on missile defence.
She arrives in the Middle East on Sunday to hold discussions with Israeli PM Ehud Olmert in Jerusalem, before travelling to the West Bank to see Palestinian President Mahmoud Abbas.
Her five-day tour will also involve meetings in Egypt and Jordan.
Correspondents say there is growing scepticism among Arab governments on whether next month's conference will tackle what they see as the core issues in the conflict with Israel.
Washington hopes for wide Arab participation but Syria has already said it is unlikely to attend unless its concerns over the Golan Heights are on the agenda.
Invites for the gathering - scheduled to take place in Annapolis, Maryland - have not been sent out yet because so much remains to be finalised.
Analysts say key bones of contention will include the shape of final borders, sovereignty over Jerusalem and a solution for Palestinians who lost their homes in the war that followed Israel's creation in 1948.
The US secretary of state will hope her Middle East tour is rewarded with more success than her visit to Moscow on Friday and Saturday.
Talks on US plans for a missile shield in Eastern Europe broke down in acrimony after Russian President Vladimir Putin made clear his anger over the project. ( BBC )