The United States has denied speaking to Iran about a prisoner exchange after Iran's President Mahmoud Ahmadinejad said Tehran has held discussions about such a swap.

Mr. Ahmadinejad also told state television Tuesday his government may release three jailed U.S. citizens in exchange for Iranians held in American prisons.

White House spokesman Mike Hammer called reports of Mr. Ahmadinejad's comments incomplete.  But Hammer said if President Ahmadinejad's comments suggest Iran is prepared to resolve the case, the U.S. would welcome that step

Mr. Ahmadinejad did not specify whether the talks involved U.S. officials, nor did he say which Iranians he wants the United States to release.

Iran has previously alleged that 11 of its citizens are being held in the United States, including a nuclear scientist who went missing in Saudi Arabia.

Iranian authorities arrested three Americans last July after they crossed into Iran from Iraq. Tehran accuses them of spying. Family members say Shane Bauer, Josh Fattal and Sarah Shourd were hiking in Iraq's autonomous Kurdish region when they strayed into Iran accidentally.

Washington has said the accusations against the Americans are unfounded, and has called for them to be released. Iran has said they will be put on trial, but has not announced a date.

The United States and Iran do not have diplomatic relations and contact between U.S. and Iranian officials is rare.

Some information for this report was provided by AFP and AP.