The United States said Wednesday that it is not interested in a proposal by Iranian President Mahmoud Ahmadinejad that some Iranians in U.S. prisons be swapped for three American citizens being held in Tehran.

"We are not interested in a swap per se. We are interested in resolving the cases of our citizens, who we think should be released immediately," said State Department spokesman Philip Crowley, adding that there are no negotiations taking place on the swap.

President Ahmadinejad said Tuesday in an interview with Iran's State TV that Iran might release three detained U.S. hikers in exchange for Iranian prisoners in the United States. "There are some talks under way to have an exchange, if it is possible."

Tehran claims that at least 11 Iranians have been detained in U. S. prisons, and that among them are a nuclear scientist who disappeared in Saudi Arabia and a former Defense Ministry official who was missing in Turkey.

The three Americans, Shane Bauer, Sarah Shourd and Josh Fattal, were arrested in Iran on July 31 after they illegally entered the country from its western boarders. The Iranian authorities have warned that the three could be tried in the country.

"There is not really an equivalence, if you will, between, say an Iranian citizen who has been indicted and / or convicted of arms trafficking in violation of international law and three hikers who wandered across an unmarked border," said Crowley.