US Secretary of State Hillary Rodham Clinton says the United States has no illusions that Iran will accept overtures to return to negotiations about its nuclear program and will not wait much longer for Teheran to respond. Both Clinton and national security adviser James Jones said in interviews aired Sunday that Washington had little choice but to deal with the government of Iranian President Mahmoud Ahmadinejad, regardless of US feelings about charges he was re-elected in a fraudulent election and sympathy for the thousands who have protested the outcome. Many protesters were arrested or killed and those jailed are now standing trial. US officials have called the court proceedings "show trials." In April, the United States sent word to Iran that Washington still hoped to see Teheran return to talks with the five permanent members of the UN Security Council and Germany about ending what is widely believed to be an attempt to build a nuclear weapon. Iran says its nuclear program is designed only for generating electricity. The US hopes to use a variety of economic enticements to lure the Iranians away from the nuclear program, fearing it will create an arms race in the Middle East. In the meantime, the Obama administration is working with the five permanent UN Security Council members - US, Britain, Russia, China and France - and Germany on a new and tougher round of sanctions should the Iranians reject or ignore the US overture. Clinton said the United States would re-evaluate its efforts to entice Iran back to the negotiating table in September. "We are under no illusions. We were under no illusions before their elections that we can get the kind of engagement we are seeking," she said in an interview with CNN's "GPS." "The president has also said, look, we need to take stock of this in September. If there is a response, it needs to be on a fast track. We're not going to keep the window open forever," she said. Jones echoed Clinton's assessment that Washington had little choice, at this point, except to deal with Ahmadinejad, who was sworn in to a second term last week. "We have to deal with the figures of authority that are in position," Jones said on NBC's "Meet the Press." Jones disclosed that the United States was officially told for the first time on Sunday by the Iranian government that it was holding three US hikers who strayed into Iran from the Kurdish region of Iraq. US and Kurdish officials say the Americans accidentally entered Iran across the poorly marked border on July 31. Reports from Iran have said Teheran was looking into whether the three were spying for the United States. But until Jones' comment, there had not been any official Iranian government confirmation that the three were in custody.