President Trump announced a proposal aimed at achieving the disarmament of Hamas and an Israeli withdrawal. Israel ramped up attacks on the Palestinian enclave.

Soon after President Trump announced a new plan last week to deliver peace and security in Gaza, the Palestinian enclave instead experienced a spike in deadly Israeli bombings, which threatened to undermine hopes for long-awaited progress.

On Sunday, Israeli strikes killed 18 people, according to the health ministry in Gaza, making it one of the deadliest days there since a troubled cease-fire came into force in October. Gaza health ministry data from the conflict does not distinguish between civilians and combatants.

Israeli strikes a day earlier killed at least two people and damaged warehouses for medical supplies, Palestinian officials said. And on Monday, the Israeli military struck a car on a beachside road, killing two, according to Gazan officials. No new Israeli strikes have been reported in Gaza since Monday evening.

With many of the plan’s details still unclear, including a timetable for the Hamas disarmament at its heart, the 15-point plan released by Mr. Trump’s Board of Peace — which also calls for an Israeli withdrawal and a new administration in Gaza — risks being undone before the specifics are worked out.

On Monday, a spokesman for the Israeli prime minister’s office, Doron Spielman, pushed back against the terms of the agreement, which Israel had not signed. “The version that has been made public does not reflect Israel’s positions,” he said in a statement. He added, “Israel has conveyed its comments and concerns on the proposed framework to our American counterparts.” He said the concerns centered on the issue of Hamas disarmament.

Nickolay E. Mladenov, a veteran Bulgarian diplomat who is the Board of Peace’s high representative for Gaza, leveled rare criticism at Israel over its attacks.

“Two days of strikes across Gaza have killed civilians and destroyed medical supplies that people depend on,” he said in a statement posted on social media on Sunday. He said that the attacks came after “intense efforts” by the mediators to reach a deal and that he and his team were “working around the clock with the parties, mediators and regional partners to de-escalate.”

In a joint statement on Monday, three countries that have served as mediators — Qatar, Egypt and Turkey — condemned what they described as “the ongoing Israeli violations” in Gaza.

The Israeli military has said that its strikes in recent days have targeted Hamas fighters and weapons infrastructure. It also said it had taken steps to mitigate harm to civilians.

Since the October cease-fire, Israel has steadily stepped up attacks across the Gaza Strip. In July, the military carried out almost daily strikes and named at least 50 militants it said it had eliminated, including what it said were Hamas members who had participated in the Oct. 7, 2023, assault on Israel that killed about 1,200 people. That attack ignited the war in Gaza, which has left more than 70,000 dead, according to officials, and much of the enclave in ruins.

On Tuesday, a mass funeral was held in Gaza City for 112 people whose bodies had been pulled from the rubble in recent weeks, according to Mahmoud Bassal, a spokesman for the civil defense, which operates under the Hamas-run interior ministry.

Israel was either showing it did not care about the agreement, he said, “or there was a fear that the point may come where the United States tells Israel to stop” and the military was striking while it still could.

On Sunday night, Mohammed Dahlan, an influential Palestinian exile and a confidant of the president of the United Arab Emirates, wrote on social media that Jared Kushner, a son-in-law and an aide to Mr. Trump, had provided assurances that he reached an agreement with Israel that it would cease its strikes. But shortly thereafter, he edited the post, deleting the reference to an agreement, and said Mr. Kushner had conveyed he was “working with the Israeli side to stop the attacks on Gaza.”

Negotiators on the Board of Peace described the new agreement with Hamas, announced by Mr. Trump last week, as a “road map” intended to cement the fragile cease-fire, disarm Hamas, secure a complete Israeli withdrawal from Gaza and enable a return to normalcy for the population and the start of reconstruction.

But key questions immediately arose over whether Hamas and Israel would carry out the agreement. According to the text, the parties were given two weeks to determine a schedule, which an international verification committee could extend.

Stark differences have already emerged over sequencing, among other issues. The agreement with Hamas stipulates that Israel must initially fulfill its obligations under the October cease-fire deal, which called for an immediate suspension of Israeli attacks.

Prime Minister Benjamin Netanyahu of Israel had pledged total victory over Hamas, along with its dismantlement. He said on social media on Tuesday that Israel would not pull back from its current positions in Gaza before Hamas had completely disarmed.

Hamas, for its part, has long touted armed struggle against Israel as the core of its ideology. The group’s weapons have so far helped it keep power in Gaza, though Hamas has said it is willing to hand over the administration of the territory to a committee of Palestinian technocrats working under the Board of Peace’s supervision.