A top American adviser has been working to establish new ways for the United States to guarantee Israel’s security in the event it no longer occupies the West Bank — part of the effort by Secretary of State John F. Kerry to restart peace talks, according to officials familiar with the strategy.

Retired Marine Gen. John R. Allen, who is serving as a special adviser to both Kerry and Defense Secretary Chuck Hagel, has been seeking to identify Israel’s potential security gaps and remedy what Prime Minister Benjamin Netanyahu had complained were outdated or incomplete assurances of cooperation and equipment from the United States, the officials said. The goal is to remove potential deal-breakers at the outset of the push for new talks before they can spoil what Kerry calls a last chance for peace between Israel and the Palestinians.

Allen, the former top U.S. commander in Afghanistan, has visited Israel twice for discussions about ways that the United States could update agreements reached with Israel during the last major push for a peace deal, in 2007 and 2008. He also held meetings with Israeli security officials this month in Stuttgart, Germany, where some of the U.S. military staff assigned to Allen is headquartered.

Allen and his Israeli counterparts are seeking “effective, innovative and feasible options that could be proposed to political leaders,” said a senior Obama administration official, who spoke on the condition of anonymity to provide the first detailed account of Allen’s mandate and progress.

The Obama administration has been publicly mum about the scope and intent of Allen’s work since he was appointed to the job in May, saying only that it is part of wider effort to improve the chances for peace. Kerry is trying simultaneously to stimulate the Palestinian economy with new private-sector investment and dust off a dormant offer from Arab nations for a blanket peace agreement that would settle most disputes with Israel.

Netanyahu has agreed to resume peace talks so long as the Palestinians drop preconditions for the negotiations. Palestinian Authority President Mahmoud Abbas is under heavy U.S. pressure to drop or soften those demands and return to talks that have been moribund for most of the past five years.

Kerry met separately with Netanyahu and Abbas during several days of shuttle diplomacy over the past week, before departing Sunday.

“The purpose is not to take issues off the table, but to drive a deeper examination of a range of issues so all parties can see what options might exist and to see if common ground can be found,” the U.S. official said.

But addressing Israel’s concerns about security threats coming from an independent Palestinian state next door at the front end of negotiations is the underlying premise of Allen’s work, others briefed on his efforts said.

An account of meetings Allen has held with Israeli officials, provided anonymously by a participant, shows that he is addressing some of the biggest potential obstacles to Israeli approval of the comprehensive peace deal Kerry wants to broker.

“The rationale behind reaching understandings on U.S. security guarantees at this point is to render certain Israeli security demands from the Palestinians moot and thus remove them from the negotiating table,” one person briefed on the effort said. The account was provided to The Washington Post on the condition of anonymity because Allen’s meetings were confidential.

Allen’s team was dismayed by the initial Israeli discussions, which participants described as less substantive and less cooperative than U.S. officials were expecting, given that Allen’s job was created to address Israeli security concerns.

George Little, a Defense Department spokesman, said Allen is “supporting Secretary Kerry’s comprehensive efforts to forge a way ahead on Middle East peace.”

“Those efforts involve discussions along the full range of diplomatic, political and security issues,” he said. “Gen. Allen’s role is focused on the security dimensions of this initiative.”

A spokesman for the Israeli Embassy in Washington said: “We are deeply committed to, and appreciative of, Gen. Allen’s mission. We are working with him with the utmost seriousness and openness to lay the essential groundwork for peace.”

Israel’s intelligence minister, Yuval Steinitz, who participated in meetings with Allen, said the Israelis were exploring their options, but he stressed, “we made it very clear that technology is not enough for us.”

Steinitz said that Israel “had very bad experiences, even with massive deployments of U.N. forces. We can’t trust only technology and international troops.” He said that despite the presence of international troops, the militant organization Hezbollah had amassed 40,000 rockets and missiles in southern Lebanon. Along the Syrian boundary in Israeli-occupied Golan Heights, Austrian peacekeepers recently pulled out after being fired upon by combatants in Syria’s civil war. “U.N. forces are there until you need them,” Steinitz said.

Steinitz emphasized that in his view Israel, “for real security,” would need to maintain control of the Jordan Valley, as well as the air and sea space around any future Palestinian state, “for decades.”

Perhaps the most contentious issue under discussion is military control over the Jordan Valley.

Netanyahu said last year that he would never sign a peace agreement that did not leave some Israeli security presence in that area, where Israel has built large Jewish settlements. Although a peace deal now would almost certainly redraw the 1967 border to include some Jewish settlements inside Israel, the new border would inevitably abut land under Palestinian control.

Other issues Allen is raising with Israel include security management of new land and maritime borders and control and surveillance of airspace around Israel and early warning stations to alert Israel of incoming missiles or rockets, two people briefed on the effort said.

Brief exploratory talks between Israeli and the Palestinians fell apart last year over Israeli security demands, both Palestinian and Israeli media reported at the time. The Israeli newspaper Ma’ariv reported afterward that Israel had softened an earlier demand that it retain sovereignty over the Jordan Valley. Tight new security measures could suffice, the paper reported.

A permanent Israeli military presence inside a newly independent Palestine would be a deal-breaker for Abbas, so the challenge would be to design an Israeli security presence of sufficient duration and size to satisfy Israel while making clear that the arrangement is not open-ended.

Although the U.S. position on many such particulars is vague, the assumption behind Allen’s work is that the United States would promise to help Israel strengthen some potential security weaknesses in the context of a final peace deal with the moderate Palestinian Authority.

A $10 billion U.S. arms package for Israel, Saudi Arabia and the United Arab Emirates announced this year is primarily aimed at countering potential threats from Iran. But its guarantee that Israel will maintain and expand its military edge over even Arab neighbors that are close U.S. partners is a model for a potential future arrangement balancing Israeli and Palestinian concerns, the senior U.S. official said.

The package deal announced by Hagel during a Middle East trip in April includes advanced missiles, refueling tankers and advanced radar for Israeli warplanes. The United States would also provide V-22 Osprey tilt-rotor aircraft for Israel that can be used for land and sea border patrol.

The two Persian Gulf nations could purchase U.S. warplanes and missiles, but the arrangement is meant to ensure that those weapons could not be used against Israel.

Possible future U.S.-Israeli military cooperation could also follow the model of the jointly developed Iron Dome missile interception system now shielding areas of Israel threatened by rockets from the Gaza Strip.

Israel withdrew from Gaza unilaterally in 2005, and the Palestinian militant faction Hamas soon took over. Israeli hard-liners skeptical of a peace deal to settle Israel’s much longer border with the West Bank often point to Gaza as a cautionary tale.

William Booth contributed to this report from Jerusalem.