Two top American defense officials spoke out against possible Israeli plans to strike Iranian nuclear sites Tuesday, as the US ramps up efforts to hold Jerusalem back from launching a unilateral campaign.

Speaking to reporters from the Pentagon, US Defense Secretary Leon Panetta said he did not believe Israel had yet made a decision on whether or not to embark on a military campaign.

“I don’t believe they made a decision as to whether or not they will go in and attack Iran at this time,” Panetta said. “Obviously, they’re a sovereign country. They’ll ultimately make decisions based on what they think is in their national security interest. But I don’t believe they made that decision at this time.”

Panetta added that he thought there was still time for sanctions against Tehran, designed to push the Iranians into abandoning their nuclear program, to take hold.

Gen. Martin Dempsey, head of the Joint Chiefs of Staff, also spoke out against reported Israeli plans, saying Israel’s air force did not have the capability to deliver a knockout blow to Iran’s nuclear program.

“I think that it’s a fair characterization to say that they could delay but not destroy Iran’s nuclear capabilities,” Dempsey said.

Earlier on Tuesday, reports surfaced that the US was seeking to assure Jerusalem that it would strike at Iran by June 2013 if all else failed.

Channel 10 news reported that Prime Minister Benjamin Netanyahu and US President Barack Obama would likely meet late next month or early in October, and Obama would seek an Israeli promise not to go it alone against Iran.

Israeli analysts have surmised that Israel may be seeking to push a reluctant Obama into backing an Israeli strike by launching a solo strike before US elections in early November.

Some believe such a move may force Obama to choose between backing Israel and losing his reelection bid.