US Secretary of State Antony Blinken was heading back to the Middle East on Monday to push a ceasefire plan, but Israeli politics and silence from Hamas raised further questions on whether he can succeed.
The top US diplomat, paying his eighth visit to the region since war broke out, was set to start the trip in Egypt and head later Monday to Israel.
Blinken is scheduled to hold closed-door talks first in Cairo with President Abdel Fattah al-Sisi, a key US partner in peace efforts, and later in Jerusalem with Prime Minister Benjamin Netanyahu.
Blinken planned the visit to push forward a proposal announced on May 31 by President Joe Biden, who has stepped up efforts to end a war that has taken a mounting toll on civilians and alienated parts of his base ahead of November elections.
But Hamas, which opened the war with a massive October 7 attack on Israel that triggered a relentless retaliatory campaign, has not formally responded.
And while Biden has described his plan as coming from Israel, the resignation on Sunday of a key centrist, Benny Gantz, from Netanyahu's war cabinet throws a new wild card on US diplomatic efforts.
Gantz, a former general who leads in polls to replace Netanyahu if new elections are called, protested that the prime minister had not made the hard decisions to enable "real victory", including by thinking out a post-war plan for Gaza.
Gantz has cast himself as a smoother partner for the United States than Netanyahu, a veteran of political squabbles with Israel's vital ally. Biden in recent weeks suspended a shipment of weapons to Israel and accused Netanyahu of prolonging the war to stay in power, an assertion on which he backtracked.
Gantz defied Netanyahu by visiting Washington on his own in March and has regularly met in Israel with Blinken, although a meeting on the latest trip was not immediately announced.
The short-term effect of Gantz leaving the war cabinet could be removing a counter-balance to Netanyahu's far-right allies, who abhor any compromise and have threatened to quit if Israel accepts the ceasefire plan.
Israel also showed Saturday it has more tools than diplomacy to free hostages -- its key priority -- with an operation that freed four Israeli captives and which Palestinian officials say killed 274 other people.
Overall Israel's retaliatory military offensive has killed at least 37,084 people in Gaza, mostly civilians, according to the territory's health ministry.
Hamas's October 7 attack on southern Israel resulted in the deaths of 1,194 people, also mostly civilians, according to an AFP tally based on Israeli official figures.
Under the plan laid out by Biden, Israel would withdraw from Gaza population centres and Hamas would free hostages. The ceasefire would last an initial six weeks, with the ceasefire extended as negotiators seek a permanent end to hostilities.
Jake Sullivan, Biden's national security advisor, said Sunday it was difficult to say how the rescue operation would affect negotiations on a ceasefire.
"If Hamas came and said yes to the deal on the table, there would be an end to the need for these kinds of operations, because the hostages would be coming out peacefully and not through military actions," Sullivan told ABC News.
In Egypt, Blinken is also expected to speak to Sisi about solutions to open the key crossing into Gaza at Rafah.
The month-long closure has worsened the humanitarian disaster in Gaza, sending prices of scarce goods skyrocketing and worsening fears voiced by the United Nations of famine in the blockaded territory.
Israel seized the crossing from Hamas and has blamed Egypt for the closure.
Egypt, the first Arab state to make peace with Israel, has hit back and said that drivers feel unsafe going through what is now an Israeli checkpoint.
Blinken was heading to the region from France, where he joined Biden on a state visit that marked the 80th anniversary of Allied troops' D-Day landing in German-occupied Normandy.
Blinken will also visit two more key Arab partners, Jordan and Qatar, before returning Wednesday to join Biden at the Group of Seven summit in Italy.
