Jared Kushner, President Trump’s son-in-law and close adviser, met with Hamas leaders in Egypt on Sunday, a Hamas official and another official briefed on the meetings said. The talks were part of a diplomatic push to advance Mr. Trump’s plan for the future of Gaza.

A U.S. official confirmed that Mr. Kushner was in Egypt for talks on Gaza, without providing further details. All three officials spoke on the condition of anonymity to detail Mr. Kushner’s meetings.

Last month, Mr. Trump announced that his Board of Peace had reached an agreement with Hamas that aimed to strip the Palestinian group of its weapons. Disarming Hamas is a key component of the president’s 20-point plan for Gaza, much of which is still unrealized nearly a year after an initial cease-fire was reached last October.

Prime Minister Benjamin Netanyahu of Israel later said he rejected the deal, appearing to put it on ice. Following the meetings with Hamas on Sunday, Mr. Kushner was expected to travel to Israel to meet with Mr. Netanyahu to discuss the situation in Gaza.

Negotiations between the U.S. government and Hamas, which the United States has designated as a terrorist organization, were once rare. But the Trump administration broke that taboo, holding multiple rounds of direct talks with the group to win freedom for the hostages Hamas seized in Israel and to end the Israeli military campaign there.

Though Mr. Kushner does not hold an official U.S. government position, Mr. Trump has tapped him, alongside former real estate developer Steve Witkoff, to lead negotiations on matters as diverse as Russia’s invasion of Ukraine and the Israeli-Hamas war.

For the deal with Hamas to go ahead, Israel would likely have to agree to a phased timeline for withdrawing its forces from the Gaza Strip in parallel with Hamas gradually handing over its weapons. Mr. Netanyahu has been loath to do so, demanding “genuine disarmament” before any Israeli withdrawals.

Analysts said Mr. Netanyahu’s position reflected Israel’s hawkish turn following the Hamas-led Oct. 7, 2023, attacks that ignited the two-year war in Gaza, as well as Mr. Netanyahu’s efforts to appeal to voters ahead of national elections this fall.

Neither Mr. Kushner nor Hamas publicly discussed their meeting in Egypt.

Hamas said a delegation of senior officials led by Khalil al-Hayya, Hamas’s political chief, had arrived in Egypt. But the group said only that they had met with Hassan Rashad, the Egyptian intelligence chief who helped broker the Gaza cease-fire talks.

Egypt’s president, Abdel Fattah el-Sisi, met with Mr. Kushner to discuss the Gaza peace process, among other issues, according to a statement from the president’s s office.