The truce between Israel and Hamas leaves big questions unresolved at the moment

Israel and Hamas reached agreement on an initial six-week truce partly by postponing their more complex disputes to an ambiguous second phase — which neither side is sure they will reach.

Under the agreement, 16 days after the initial ceasefire, Israeli and Hamas officials are expected to begin negotiating the following steps: an end to the war, the release of the remaining living hostages from Gaza and the withdrawal of Israeli forces from the area.

Israeli leaders have long insisted that they will not end the war until Hamas is destroyed. That seemed far from reality on Sunday when Hamas activists, some brandishing rifles, spread out across parts of Gaza in pickup trucks in a show of authority to Palestinians and Israelis alike.

Israel and Hamas have kept some of their bargaining chips. At the end of the 42-day truce, Hamas will still hold about two-thirds of the remaining 98 hostages, including dozens who are believed to be dead. Israel will still occupy parts of Gaza, holding senior prisoners, including Marwan Barghouti, the famous Palestinian militant leader and political figure.

But as part of the talks, the Israeli government will likely have to choose whether it is willing to choose one of its war aims, the repatriation of hostages, rather than another, the destruction of Hamas. The selection of hostages may threaten Prime Minister Benjamin Netanyahu’s grip on power in Israel.

In the meantime, the two sides have agreed to postpone reaching a decisive agreement on the end of the war and the future of Gaza, and hope that a 42-day ceasefire will serve their advantage, said Shlomo Brom, a retired Israeli brigadier general. He added that Hamas, in particular, “hopes that the new dynamic will prevent Israel from returning to fighting.”

The decision to accept a temporary ceasefire has created deep fissures within Mr. Netanyahu’s ruling coalition, which is teeming with hardliners. Itamar Ben Gvir, the far-right National Security Minister, resigned from the government in protest, and his Jewish Power party withdrew from the coalition on Sunday.

The Religious Zionist Party, led by Bezalel Smotrich, has threatened to withdraw from the coalition as well, if Netanyahu fails to renew the fighting after the end of the 42-day truce. If Mr. Smotrich’s party also leaves, Mr. Netanyahu’s government would hold less than half the seats in the Knesset, Israel’s parliament, which could lead to the fall of the government and force new elections.

On Saturday night, Netanyahu confirmed that the ceasefire is temporary at the moment. He said that Israel reserves the right to return to war if “the second phase negotiations are ineffective,” adding that President-elect Donald J. Trump would support Israel’s decision.

“We reserve the right to return to war, if necessary, with the support of the United States,” Netanyahu said in a televised speech.

The fragility of the truce was underscored on Sunday morning when Hamas did not immediately hand over the list of hostages to be released to Israel, delaying the ceasefire for nearly three hours. Analysts say the deal is likely to see many similar tests over the next few weeks as both sides flex their muscles.

The families of the Israeli hostages who are still being held in Gaza called on the Israeli government to return the remaining prisoners to their homeland by implementing all stages of the deal. Noa Argamani, the freed hostage whose boyfriend, Avinatan Or, remains in captivity, said she was heartbroken that he would not be released this round.

“The progress that has been made in the last few days is a very important step, but the deal must be completed fully, completely, in all its stages,” Ms. Argamani said in a speech in Miami on Thursday.