Israel’s caretaker prime minister, Yair Lapid, pushed President Biden on Thursday to go beyond his public commitment to stopping Iran from ever obtaining a nuclear weapon, declaring that all democratic nations must vow to act if the Iranians continue “to develop their nuclear program.”

The distinction between Mr. Biden’s commitment and Mr. Lapid’s declaration was more than semantic: It goes to the heart of their countries’ differing approaches in dealing with Iran’s nuclear ambitions. Israel has conducted a series of covert sabotage and assassination operations to slow Iran’s ability to enrich nuclear fuel, while Mr. Biden has insisted that diplomacy, and a restoration of the 2015 Iran nuclear agreement, are the best way to find a permanent solution.

“If they continue to develop their nuclear program, the free world will use force,” Mr. Lapid said at the opening of a news conference in Jerusalem after the two leaders met as part of Mr. Biden’s four-day visit to the Middle East. During those remarks, Mr. Biden listened attentively but never repeated that commitment. Instead, he stuck to talking about blocking Iran from obtaining a weapon — not a program that might be intended to develop one.

In the short news conference, Mr. Biden was pressed directly on whether he would raise the case of a murdered Saudi dissident, Jamal Khashoggi, when he meets with Saudi leaders on Friday. Crown Prince Mohammed bin Salman was deemed responsible for the brutal 2018 killing in Istanbul of Mr. Khashoggi, a columnist for The Washington Post who was living in the United States.

Mr. Biden said on Thursday that his views on the murder were well-known — but he stopped short of saying whether he would specifically raise the dissident’s name during his meeting.

“My views on Khashoggi have been absolutely, positively clear,” Mr. Biden said, adding that he had never hesitated to speak openly to allies and adversaries about human rights. But with the American leader scheduled to fly directly from Israel to Jeddah on Friday — a flight that itself says much about the changed environment in the Middle East — administration officials were still debating how, if at all, he should raise the case in public comments on Saudi soil.

In other cases, recently including Cuba and Venezuela, Mr. Biden has stressed that his administration is making democracy and respect for human rights the paramount consideration for dealing with other nations’ leaders. But on Thursday in Jerusalem he said, “the reason I am going to Saudi Arabia is to promote U.S. interests,” which include getting the kingdom to pump more oil from its somewhat modest spare capacity.

Mr. Biden’s news conference with Mr. Lapid was the only scheduled set of extensive remarks on his trip to the Middle East. He used it to bolster the blossoming relationship between Israel and a handful of Arab states, including the creation of a joint air defense zone to protect against Iranian drones and missiles. Administration officials say that while they are pushing for full diplomatic relations between Saudi Arabia and Israel, they expect only incremental progress toward that goal on this trip.

He said that he had been impressed by a demonstration on Wednesday of Israelis and Americans using the Iron Dome rocket-interception system, and a new system named Iron Beam, still a prototype, that uses lasers.

“These technologies and advances are critical, Mr. Biden said. “Every rocket that is intercepted is a potential life, maybe more, that is saved.”