President Trump held a lengthy Oval Office meeting on Wednesday about the postwar future of the Gaza Strip, even as a cease-fire deal between Israel and Hamas remains elusive and residents of the territory face a humanitarian crisis.

Mr. Trump met for more than 90 minutes with his special envoy, Steve Witkoff, as well as with Mr. Trump’s son-in-law and former White House adviser Jared Kushner, according to two people briefed on the matter.

Secretary of State Marco Rubio, who also serves as Mr. Trump’s national security adviser, was there for portions of the meeting, as was Tony Blair, the former prime minister of the United Kingdom who has since begun a global institute, according to the people, who spoke on the condition of anonymity because they were not authorized to speak publicly.

Mr. Kushner did not respond to a message seeking comment. He has never been fully gone from Mr. Trump’s orbit, taking a behind-the-scenes role in recent years. During the first Trump administration, he led the way on Mr. Trump’s biggest diplomatic achievement, the Abraham Accords, establishing diplomatic relations between Israel and three Arab states, and has his own business and other ties to the region.

Details of Wednesday’s meeting were not immediately clear. Mr. Witkoff revealed plans for the meeting in a Fox News interview on Tuesday, saying that the administration was assembling “a very comprehensive plan” to deal with the region.

Mr. Trump has spoken in broad terms about a bright future for Gaza — but not necessarily one that includes the Palestinians who live there. He has mused about turning the territory into a luxury resort and, at times, moving its residents elsewhere.