The Israeli military on Tuesday carried out a deadly strike on a seaside cafe in Gaza City, one day after President Trump’s son-in-law Jared Kushner visited Israel in an effort to restart American peace efforts.

Mr. Kushner met in Jerusalem on Monday with the Israeli prime minister, Benjamin Netanyahu, in an attempt to advance Mr. Trump’s 15-point proposal for disarming Hamas, restoring calm to Gaza and beginning the reconstruction of the war-torn enclave.

Last month, Mr. Trump announced that his Board of Peace had reached an agreement with Hamas to disarm, and the agreement stipulated, in part, that Israel must fulfill its obligations under the October cease-fire deal, which called for immediately suspending Israeli attacks.

The airstrike on Tuesday killed at least seven people, including a child, and wounded 14, according to Dr. Mohammad Abu Salmiya, head of Al-Shifa Hospital. Several of those were in critical condition, and medical workers were “trying to save their lives,” he said.

In a statement, the Israeli military said that it had struck Hamas commanders planning to attack Israeli troops in the northern Gaza Strip, adding that “steps were taken to mitigate harm to civilians.” It noted in a separate statement that one of those targeted had “infiltrated Israeli territory and participated in the Oct. 7 massacre,” referring to the 2023 Hamas-led attack on southern Israel that ignited the war in Gaza.

Soon after Mr. Trump announced the disarmament agreement with Hamas, Mr. Netanyahu rejected it. And on Tuesday, Israel’s defense minister, Israel Katz, said the strike signaled Israel’s unwavering position.

“We eliminate threats, take out terrorists and exact a price from anyone who took part in the Oct. 7 massacre,” Mr. Katz wrote on social media, adding that this was how the Israeli military “acted today” and “that is how it will continue to act with force in order to protect our soldiers and ensure peace and security.”

Mr. Katz said that “Israel’s policy in Gaza” had been “made clear” by him and Mr. Netanyahu.

After the meeting with Mr. Kushner on Monday, Mr. Netanyahu’s office said in an English-language statement that the two sides had “deep and constructive” discussions — but in a separate Hebrew-language statement to the local news media the Israeli government was more circumspect about the prospects for progress.

The Israeli attack hit a seaside cafe by Gaza’s port named The Sweet and the Bitter. Fayez Qreqa, a local journalist who had been in the port area at the time, said he had just stepped out of his car when he heard an explosion. He said that the area had been crowded, as usual on a summer day, and that he saw dead and wounded people “blown toward the sea.”

Dr. Basem Naim, a member of the Hamas Political Bureau, called the attack “treacherous.” He said in a statement that the Board of Peace “bears responsibility for the continued killing,” arguing that some of its statements “are interpreted as a green light for further bloodshed.”

Mr. Kushner, in a Fox News interview published on Monday, said that progress had been made in his meetings but that “time will tell” whether the plan will be implemented, saying Hamas must first show its willingness to disarm.

“We will not allow Gaza to be rebuilt until demilitarization occurs,” Mr. Kushner said. “We’re also not going to restrict Israel’s right to defend itself if there are any imminent threats.”

Referring to Hamas, he added, “If they don’t follow through now on their commitment, everyone will see that they’re not genuine about peace, and then Israel will have a lot more support from the U.S. and others to go and finish the job.”

There has been significant disagreement over the sequencing of the plan, which U.S. officials envision as a phased process, with Hamas turning over its weapons in stages while Israel gradually withdraws from the enclave.

Israel has insisted that its forces would not carry out any withdrawal until Hamas is disarmed.

When Mr. Kushner met with Hamas officials on Sunday in Egypt before heading to Israel, they presented him with a list of what they said were Israel’s violations of the October cease-fire agreement, according to a Hamas official and two people briefed on the talks. They said Mr. Kushner promised to speak to Mr. Netanyahu about Israel’s upholding its end of the agreement.