President Trump said on Monday that there was “a good chance” a new round of diplomacy with Iran could yield a breakthrough, but warned that he would quickly resume the airstrikes he paused over the weekend if that did not happen.

“We’re talking right now,” Mr. Trump told reporters aboard Air Force One. “Iran took a beating over the last 14 days, and they asked us very nicely, ‘please stop, let’s meet,’” he said, an assertion that Iran quickly denied.

Having failed to achieve his goals through two weeks of renewed attacks on Iran, it is unclear whether Mr. Trump can expect better results through more negotiations, including on his crucial objective of restoring free navigation to the Strait of Hormuz.

Former U.S. officials said that a defiant Iran probably sees Mr. Trump’s leverage waning fast as the November midterm elections approach. Some top Republican officials are already urging him to finish the conflict.

Yet Mr. Trump will face a crosswind on Tuesday when Prime Minister Benjamin Netanyahu of Israel visits the White House. Mr. Netanyahu favors continuing the war and is likely to make that case to Mr. Trump, analysts said.

While Mr. Trump insisted that the recent U.S. attacks had led Iran to request new talks with his administration, Iran denied that claim and gave no sign that it was prepared to make new concessions or even speak directly with American officials.