The United States is readying sanctions against Iran, possibly targeting the Iranian Revolutionary Guard Corps, local media reported on Wednesday. As a year-end deadline for Iran to engage with world powers on its nuclear program looms, the Obama administration has determined Iran is unlikely to change its refusal to cooperate, and is now deciding on the precise contours of sanctions, The Washington Post quoted unnamed administration officials as saying. High on the list of possible targets is the elite Iranian Revolutionary Guard Corps, which is playing an increasingly important role both politically and economically. The paper said it's also centrally involved in clashes between anti-government protesters and the security forces in the recent outbreak of violence in Tehran and elsewhere. The United States is likely to pursue sanctions in three ways simultaneously. First through the United Nations Security Council, which has imposed three rounds of sanctions already on Iran; second with like-minded countries; third unilaterally. The administration's unilateral sanctions are likely dealt through the Treasury Department. Treasury Undersecretary Stuart A. Levey and his team have been gathering ammunition for a financial assault on Iran for the past year, according to the report. Levey spearheaded the former Bush administration's target of the Revolutionary Guards and its nine front companies, and played a central role in imposing steep fines on financial companies which violate sanctions against Iran, including a 536-million-U.S.- dollar fine on Credit Suisse. The report quoted a high-ranking U.S. official as saying the administration wanted to avoid alienating the Iranian public, and the sanctions would be used to pressure Iran back to negotiating table. Iran is at the center of an international dispute over its nuclear ambitions. Western powers suspect Iran of attempting to build nuclear weapons. However, Tehran says its nuclear program is aimed at generating nuclear energy for civilian purposes. The United States has threatened sanctions against Iran if it doesn't accept a UN-backed uranium-swap deal by the end of the year. 