U.S. Secretary of State Hillary Clinton said Monday that the United States has begun discussing with its allies methods of "pressure and sanctions" to take on Iran over the latter's contentious nuclear program, emphasizing that the goal was to stop the Islamic regime without harming innocent civilians.

"We have begun discussions with our partners and like-minded nations about pressure and sanctions," said Clinton.

"Our goal is to pressure the Iranian government, particularly the Revolutionary Guard elements without contributing to the suffering of ordinary [Iranians] who deserve better than what they are currently receiving," she added.

A State Department official said that the goal was to keep the "door to dialogue" open, but added that the U.S. "would not wait forever."

"We have avoided using the term "deadline" ourselves, since we have made clear that the door to dialogue will remain open," said the official. "But we have also made clear that we will not wait forever, and discussions on pressure and sanctions with our international partners have already begun."

Reiterating Clinton's remarks, the official said: It's not appropriate to comment on the details of those discussions, except to say that our objective is to pressure the Iranian government without contributing to the suffering of ordinary Iranian citizens."

According to the official, the U.S. was growing wary of Iran's continued defiance of international demands, which he said had contributed to the recent discussion with its allies.

"The results of our efforts to engage the Iranians directly have not been encouraging. And we remain disappointed at Iran's non-response to a proposal for the Tehran Research Reactor," said the official.

"The Iranian government essentially announced a deadline to receive a positive response to their unacceptable counter-offer," he added, referring to the West's offer to export uranium enrichment off Iranian territory. "This sort of behavior only increases our concerns and those of others in the international community, about Iran?s intentions."

The official said that the U.S. and its allies remained committed to the Iranian opposition's efforts to reform the Islamic system, amid a violent crackdown which has left dozens of demonstrators dead and hundreds more arrested.

"Iran is going through a turbulent period. Even as we seek to address our concerns about Iran's nuclear program, including through offers of direct dialogue, we stand firmly with those in Iran who are peacefully demanding their universal rights to assemble, to speak publicly, and seek decent treatment from their government," he said.