Tehran's prosecutor said the country will take the $500,000 bail Sarah Shourd posted unless she returns for her Nov. 6 espionage trial.
Abbas Jafari Dowlatabadi was quoted by the semi-official ISNA news agency as saying that Sarah Shourd can return to Iran and defend herself at the court.
Shourd was freed Oct. 11 after 13 months in a Tehran prison and returned to the United States. Her fiance, Shane Bauer, and their friend Josh Fattal remain in prison and all three face trial on spying charges.
"Shourd has said she will return. According to the rules, we can invite them." ISNA quoted Dowlatabadi as saying. "She can attend the court and defend herself. But the bail will be confiscated if she doesn't return."
The three Americans, all Cal grads, were reportedly hiking in July 2009 in northern Iraq's Kurdistan region, near the border, when Iranian forces took them into custody and accused them of intentionally crossing.
Iran initially accused them of illegal border crossing then later raised spying allegations. The U.S. government says the three are innocent.
According to a U.S. military report that is among a huge cache of documents posted Friday by the WikiLeaks website, the three were on the Iraqi side of the border at the time.