U.S. Defense Secretary Robert M. Gates promised Israeli leaders Monday that American overtures to Iran are "not open-ended" and said the Obama administration is ready to press for tougher economic sanctions if diplomacy fails to halt what the two allies say is Iran's progress toward building a nuclear weapon.

Gates' brief visit to Jerusalem was aimed at easing tension between the United States and Israel over how to confront Iran, and the differences were evident at his only public appearance here. Speaking to reporters alongside Gates, Israeli Defense Minister Ehud Barak made it clear that he did not favor the U.S. strategy of engagement with Iran and said three times that Israel would not rule out a preemptive military strike if it deemed that talks were not working.

But later, in Amman, Jordan, Gates told reporters that Israeli Prime Minister Benjamin Netanyahu had assured him that as long as there was a time limit on the diplomatic approach, "the Israelis were prepared to let it go forward."

Iran's disputed June 12 presidential election and subsequent unrest have complicated U.S. efforts to engage the country's leaders. But Gates said in Israel that President Obama still hoped for an Iranian response to the overtures in time for the United Nations General Assembly session in late September. Obama has said he wants to see progress in talks with Iran by year's end.

"The timetable the president has laid out still seems to be viable and does not significantly increase the risks to anybody," Gates told reporters in Jerusalem after meeting with Barak.

According to U.S. and Israeli intelligence estimates, Iran is within one to three years of developing nuclear weapons capability.

Iran insists its nuclear program is geared exclusively toward the generation of electricity. Despite United Nations sanctions and other international pressures, it has continued to add centrifuges for enriching uranium.

In Amman, Gates spelled out what Iran might expect if it refused the offer of international arms control talks this year or Obama's wider offer of better relations with Washington. He said the U.S. would try to abandon the current international policy of gradually escalating levels of pressure and seek support for "significant additional sanctions."

"Our hope remains that Iran would respond to the president's outstretched hand in a positive and constructive way, but we'll see," Gates said.

Israel has chafed at efforts by the Bush and Obama administrations to keep it from acting militarily against Iran. Gates and Adm. Michael G. Mullen, chairman of the Joint Chiefs of Staff, have warned that an Israeli strike against Iranian nuclear facilities would destabilize the region, and Obama has said the U.S. is "absolutely not" giving its approval for such an attack.

During the news conference, Barak was asked how long Israel was willing to risk its security by holding back on a strike against Iran.

"I don't think that it makes any sense at this stage to talk a lot about it," Barak replied. "Our position is very clear. At the present, we are in no position to tell the administration whether to run an engagement with Iran or not. But if there is an engagement, we believe it should be short in time."

Meanwhile, he added, "we clearly believe that no option should be removed from the table. This is our policy. We mean it and we recommend to others to take the same position, but we cannot dictate to anyone."