A senior Iranian prosecutor accused three Americans detained on the border with Iraq of espionage on Monday, the first signal that Teheran intends to put them on trial.
The move could set up the Americans - who relatives say were hiking and strayed across the border from Iraq - as potential bargaining chips in Iran's standoff with the West. The announcement caught Washington and Teheran were in a deadlock in negotiations over Iran's nuclear program.
Shane Bauer, Sarah Shourd and Josh Fattal, all graduates of the University of California, Berkeley, were arrested July 31 after straying over the Iranian border from northern Iraq.
US Secretary of State Hillary Rodham Clinton called for the release of the three. "We believe strongly that there is no evidence to support any charge whatsoever," she told reporters in Berlin. "And we would renew our request on behalf of these three young people and their families that the Iranian government exercise compassion and release them, so they can return home."