Updated

Senator Joe Lieberman, I-Conn., in what his staff is billing as "a major policy address" on Wednesday, plans to deliver a sharp warning for Iran's leadership that military action should remain on the table should the authoritarian regime refuse to halt its pursuit of nuclear weapons.

In a speech on "the Future of American Power in the Middle East," to be delivered at the Council on Foreign Relations, the senator, a senior member of the Armed Services Committee, will "up the rhetorical ante against Iran", according to an aide, and discuss the next stage if current sanctions do not work.

"It is time to retire our ambiguous mantra about all options remaining on the table. Our message to our friends and enemies in the region needs to become clearer: namely, that we will prevent Iran from acquiring a nuclear weapons capability -- by peaceful means if we possibly can, but with military force if we absolutely must," Lieberman is expected to say, according to his staff who provided the excerpt to Fox News.

Iran has steadfastly denied it is seeking nuclear power for nefarious purposes.

Still, these are strong words that echo remarks recently made by a close Lieberman ally, Sen. Lindsey Graham, R-S.C.

A respected military lawyer and committee member, Graham last week was the first senator to openly support direct military intervention in Iran, saying, "From my point of view, if we engage in military operations as a last resort, the United States should have in mind the goal of changing the regime...not by invading (Iran), but by launching a military strike by air and sea."

Graham framed the argument as almost an inevitable outcome.

"If you use military force against Iran, you've opened up Pandora's box," Graham warned, but quickly added, "If you allow Iran to get a nuclear weapon, you've emptied Pandora's box. I'd rather open up Pandora's box than empty it."