Former United States Secretary of State Condoleezza Rice implored U.S. negotiators to leave the option of a military strike on the table when they meet with Iranian officials in Istanbul this weekend to attempt to convince Tehran to abandon its nuclear weapons program.

The negotiations will involve the United States, Great Britain, Germany, Russia, China, and France. American and European officials have been bearish on the prospects for the talks, though the White House insists “it’s a good first step.”

“The most important thing we can do when we go to the talks is not to offer to begin to lessen sanctions, because that takes the pressure off,” Rice told the Heritage Foundation in an exclusive interview on Friday.

But Rice added that the U.S. must make clear its willingness to engage Iran militarily if it continues to pursue nuclear weapons. Officials must “remind the Iranians that the president of the United States does have a military option and is prepared to use it,” she stated.

The Iranians’ belief that the United States would, if necessary, use that military option, Rice added, is “the only way they’re going to come to some resolution, if indeed they will.”

Congressional leaders echoed Rice’s call for a strong American posture in the negotiations, a position also held by the Heritage Foundation. “Instead of forfeiting our position of strength,” said Rep. Ileana Ros-Lehtinen (R-FL), who chairs the House Foreign Affairs Committee, “the administration should increase pressure on Iran.”

Rice warned that if the negotiations do not provide a meaningful resolution, military action by either the United States or Israel is almost unavoidable.

“If the Iranians are close to a place where they cannot be stopped from getting a nuclear weapon, then I don’t think there’s any other option” but a military strike. Rice added that the strike could come from either the United States or Israel.

In the event that Israel pursues a military strike, as it has repeatedly warned, Heritage has detailed what a sound U.S. response should look like.