US Secretary of State John Kerry arrived in the Middle East on his ninth trip of the year, continuing shuttle diplomacy aimed at securing an Israeli-Palestinian peace deal by spring.
Kerry headed off to meet Palestinian President Mahmoud Abbas as soon as his plane landed on Thursday and is set to see Israeli Prime Minister Benjamin Netanyahu on Friday. He will be pressing a West Bank security plan in the closed-door talks.
Both sides are sceptical, but US officials hope that winning approval for the plan will unblock negotiations on other issues like borders, the status of Jerusalem and the fate of Palestinian refugees.
With US facilitation, Israel and the Palestinians agreed to resume peace talks in August, with a nine-month target for reaching agreement.
Kerry's latest visit comes amid few, if any, tangible signs of progress and Palestinian unhappiness with the security plan.
"This is an ongoing discussion," State Department spokeswoman Jen Psaki said on Wednesday, two days after Kerry met with each side's top negotiators in Washington.
"Certainly we expect they will talk about security, as they will discuss other issues."
Kerry, along with special US Middle East peace envoy Martin Indyk, met separately and then together on Monday with chief Israeli negotiator Tippi Livni and her Palestinian counterpart, Saeb Erekat, for about three hours, Psaki said.
Livni and Erekat were in Washington for a Middle East conference at which President Barack Obama, Netanyahu and Kerry all participated.
That same day, though, a senior Palestinian official railed against US attempts to broker a broad outline of an Israeli-Palestinian peace deal, saying Kerry is breaking a promise to try to negotiate a final agreement in the current round of talks.
The Palestinians are concerned that a framework deal will accommodate very specific Israeli security demands while offering only vague promises to the Palestinians, said top Abbas aide Yasser Abed Rabbo.
Kerry and Obama both said over the weekend that the US is pursuing a framework agreement, but they did not provide details.
Obama said it's possible to reach such an outline over the next few months.
The State Department stressed that the US remains focused on a final deal and not an interim one, although officials acknowledge there may have to be more than one step to achieve a comprehensive agreement.
Security arrangements between Israel and a future Palestine would be central to such a framework.
Kerry has argued that progress in negotiations is only possible if Israeli security concerns are addressed first.
The security proposals presented last week to Abbas and Netanyahu include arrangements for the border between Jordan and a state of Palestine.
US officials have refused to discuss details but Palestinian officials, speaking on condition of anonymity because they were not authorised to discuss the details of the negotiations, say it would give Israel final say at that border for at least 10 years and would also have a military presence in the strip of land next to it, the West Bank's Jordan Valley.
Israeli officials have said they fear weapons could be smuggled into a future Palestine if Israel gives up control over the West Bank-Jordan border.
Abbas has said he is willing to accept an international presence there, but not Israeli forces.
The Palestinians want a state in the West Bank, Gaza and East Jerusalem, lands Israel captured in 1967, but are willing to accept minor land swaps in drawing the final border to accommodate some of the settlements Israel has built on war-won land.
Netanyahu has refused to commit to what the Palestinians and most of the international community considers a basic ground rule - that border negotiations use the 1967 lines as a starting point.