WASHINGTON (CNN) -- A diplomatic solution with Iran is still possible, Secretary of Defense Leon Panetta said Wednesday.
"We have always expressed a willingness to try to do that," Panetta said at a Pentagon briefing. Panetta was responding to a report from Iran that said President Barack Obama had proposed direct talks in a letter passed to Iranian leadership.
Panetta refused to comment about specific communications but said diplomacy is always an option to pursue.
The U.S. recently sent a letter to Iran warning about blocking the Strait of Hormuz, among other communications, CNN reported earlier this week. The United States has suggested to Iran that the two sides establish a channel of direct communication to ensure miscalculations don't escalate.
The choice to talk is Iran's, said State Department spokeswoman Victoria Nuland.
"If you, Iran, are prepared to engage seriously and come clean about your nuclear program and demonstrate to the world that you have no military intent," the United States is open to engagement, Nuland said.
While diplomacy is an option, Panetta noted that, given threats made by Iran, the U.S. also is willing to respond militarily.
Two U.S. officials told CNN's Elise Labott the letter the Obama administration sent to Iran did not ask for negotiations, it suggested establishing a direct channel of communications to ensure no miscalculations escalate the situation.
The letter, the officials said, reiterated the administration's stance that blocking the Strait of Hormuz would be a "red line" for America. The sources would not say who wrote the letter or to whom it was directly addressed.
Iran's semi-official news agency Fars cited an Iranian lawmaker, Ali Motahari, as quoting from the U.S. letter and saying, "The first part of the letter contains threats and the second part contains an offer for dialogue."
Motahari told Fars that the U.S. letter said closing the Strait of Hormuz would be a "red line" for the United States. Motahari added, "In the letter, Obama has announced readiness for negotiation and the resolution of mutual disagreements," according to Fars.
Officials at the White House, State Department and Pentagon would not comment on the content of the letter at various press conferences on Wednesday. But various officials, including Panetta, noted the administration is open to talking with Iran provided the Iranians disclose the extent of their nuclear program.
White House spokesman Jay Carney said at Wednesday's White House briefing that "there is a path here towards renewed talks and a path here for Iran to pursue if it so chooses, that would allow it to get right with the international community."
But Carney added, "Iran has shown no inclination thus far to make that choice, to make that decision."
The United States is not changing its military posture in the region in response to recent threats from Iran to close the Strait of Hormuz, a key transit point for oil, Panetta said. He noted that the current U.S. presence of Navy and other military assets in the region is sufficient, though alternatives are always under consideration for different contingencies.
"We obviously always continue to make preparations to be prepared for any contingency, but we are not making any special steps at this point in order to deal with the situation. Why? Because, frankly, we are fully prepared to deal with that situation now," Panetta said.
Panetta's comments come as Israel's defense minister appeared to push back on the notion that Israel was ready to strike against Iran.
Israel's Defense Minister Ehud Barak said Wednesday that an Israeli decision on whether to strike Iran's nuclear program was "very far off."
Speaking to Israeli Army Radio, Barak would not offer a concrete estimate as to when he believes Iran may develop a nuclear weapon.
The United States and Israel recently put off a joint exercise that appeared to be aimed at sending a message to Iran. Asked at the Pentagon, Panetta said the postponement was to better prepare for the exercise.