International hopes of reaching a cease-fire in the Gaza Strip before the Muslim holy month of Ramadan were dashed on Sunday, hours before Palestinians and other Muslims were to begin the month of daytime fasting, as Hamas repeated demands for a comprehensive cease-fire, which Israel has rejected.

Egypt, Qatar and the United States had sought to broker a truce between Israel and Hamas before the start of Ramadan on Monday, and there had been optimism for a last-minute deal that would allow for the release of some Israeli hostages held in Gaza and Palestinians held in Israeli prisons.

But weeks of indirect negotiations have stalled, and a top Hamas political leader, Ismail Haniyeh, said in a televised speech on Sunday that Hamas wanted an agreement that would end the war, guarantee the withdrawal of Israeli forces from Gaza, return displaced Palestinians to their homes and provide for the humanitarian needs of Gazans.

Israel “wants to get its prisoners back and then resume the war on our people,” he said.

Mr. Haniyeh said if the mediators were to inform Hamas that Israel was committed to ending the war, withdrawing from Gaza and permitting the return of displaced people to the north, then the Islamist group would be ready to show flexibility on the issue of exchanging Palestinian prisoners for hostages.

“The enemy must understand that it will pay a price on the issue of an exchange, but the top priority is protecting our people, ending the aggression and massacres, returning the displaced people to their homes, and opening a political horizon for our issue and people,” he said.

Some Palestinians in Gaza have criticized Hamas, arguing the group was holding up negotiations in order to press Israel into freeing more Palestinian prisoners.

In an interview with Politico that was published on Sunday, Prime Minister Benjamin Netanyahu of Israel suggested a cease-fire was not imminent, saying that he would “like to see another hostage release” but that there had not been a breakthrough in negotiations.

“Without a release, there’s not going to be a pause in the fighting,” he said.

Israel has said it must wipe out Hamas’s military and governing abilities in Gaza before agreeing to end the war. It also has said a key goal of the war was the return of all the hostages taken in the Hamas-led attack on Israel on Oct. 7.

On Friday, David Barnea, the chief of the Mossad, Israel’s intelligence agency, met with the C.I.A. director, William J. Burns, in an effort to advance a deal to release hostages, the Israeli spy agency said. The Mossad accused Hamas of seeking to inflame the region at the expense of Palestinians in Gaza, but said that ongoing talks were aimed narrowing the gaps between Israel and Hamas.

In an interview with MSNBC on Saturday, President Biden said that he remained hopeful that the United States could still help broker a cease-fire between Israel and Hamas as Ramadan approached, kicking off a month of family celebrations and nightly feasts.

“I think it’s always possible,” Mr. Biden said.