JERUSALEM: Iran's proposals in nuclear talks with world powers are unworkable, US Secretary of State Hillary Clinton said Monday, warning the US would use “all elements of its power” to prevent Tehran going nuclear.

Speaking at a press conference in Jerusalem following a day of talks with top Israeli officials, Clinton said Iran had yet to make the decision to turn back from its nuclear ambitions, which much of the West believes masks a drive for atomic weapons.

“I made very clear that the proposals we have seen thus far from Iran within the P5+1 negotiation are non-starters,” she said of the latest round of talks, which took place in Istanbul earlier this month.

“Despite three rounds of talks it appears that Iran has yet to make the strategic decision to address the international community's concerns and fulfill its obligations.” Iran's leaders still had the opportunity to make the right decision, but if it failed to do so, Washington would stop at nothing to prevent it from developing a nuclear weapon, she said.

“We will use all elements of American power to prevent Iran obtaining a nuclear weapon,” she said in remarks which carried an implied threat of military action - a course of action never ruled out by Washington.

She made her remarks just days after the United States imposed a wave of fresh sanctions on Iran, targeting companies tied to Tehran's procurement, petroleum, and shipping networks.

Thanks to US efforts to rally the international community to tackle the Iranian nuclear threat, Tehran was “under greater pressure than ever before,”she said.

“That pressure will continue and increase,” she added.

Israel believes a nuclear Iran would pose an existential threat to the Jewish state and has refused to rule out a military strike on its nuclear facilities. It has warned that the current level of diplomatic pressure and sanctions is not putting enough pressure on the Republic.

But Clinton said the Obama administration was “in close consultation” with Israel over ways to increase the pressure on Tehran.

“We talked about concrete steps that we can take to continue to build the pressure,” she said. “We are pressing forward in close consultation with Israel.

“And I think it is fair to say we are on the same page at this moment, trying to figure our way forward to have the maximum impact on effecting the decisions that Iran makes,” Clinton said.

“We all prefer a diplomatic resolution and Iran's leaders have the opportunity to make the right decision. The choice is ultimately Iran's.”

Earlier, Clinton told President Shimon Peres the US was “committed to building and maintaining a wide coalition to deny Iran the ability to acquire nuclear weapons.”

She reassured the Israeli leader that the tough economic sanctions imposed on Tehran “will continue to become harsher,” a statement from the Israeli president' office said.

Pere, who is known to favour diplomacy over the idea of a military strike, expressed confidence in Washington's tough stance.

“I think the coalition we have built, and the measures you have taken are beginning to have their impact... they are the right start,” he said.

“We appreciate very much your position. We trust its depth and dedication and determination and we feel partners of this coalition.”