In Washington on Monday, President Obama urged Prime Minister Benjamin Netanyahuat the White House to give diplomacy and economic sanctions a chance to work before resorting to military action. But Mr. Netanyahu said later: “We waited for diplomacy to work; we’ve waited for sanctions to work; none of us can afford to wait much longer.”

With sanctions tightening around Iran’s oil and banking sectors, Tehran’s representative at the I.A.E.A. at its headquarters in Vienna, said in a statement on Tuesday that Iran will permit the nuclear agency’s inspectors to visit the secret Parchin military complex, southeast of the Iranian capital, in what was termed a goodwill gesture, the ISNA news agency said, according to The Associated Press.

But the statement also said the visit requires an agreement on guidelines for the inspection. The I.A.E.A. believes that secret military work has been carried out there and has been pressing for access.

Last month, a senior I.A.E.A. delegation held its second round of talks in a month Tehran with Iranian officials in Tehran.

“During both the first and second round of discussions, the agency team requested access to the military site at Parchin. Iran did not grant permission for this visit to take place,” the I.A.E.A. said at the time.

“Intensive efforts were made to reach agreement on a document facilitating the clarification of unresolved issues in connection with Iran’s nuclear program, particularly those relating to possible military dimensions. Unfortunately, agreement was not reached on this document,” the statement said.

“It is disappointing that Iran did not accept our request to visit Parchin during the first or second meetings,” I.A.E.A. Director General Yukiya Amano said. “We engaged in a constructive spirit, but no agreement was reached.”

The reported offer to permit access to the Parchin site was the second apparently conciliatory gesture by Tehran in as many days. On Monday, the Supreme Court of Iranhas tossed out the death penalty conviction of a former United States Marine accused of spying and ordered a retrial in a separate court, Iranian news services reported.

The reports quoted a state prosecutor as saying that shortcomings had been found in the case against the American, Amir Mirzaei Hekmati, and that a new trial would be held.