The federal prosecutor had recommended a prison term of time served for the 30-year-old mother's role in the illegal plot to trade with Iran, a U.S.-designated terrorist nation. U.S. District Judge James Cohn imposed the sentence at an April 25 hearing in Fort Lauderdale federal court.

But on Tuesday that smooth resolution unraveled. Determining the sentence had been a mistake, Cohn extended Gholikhan's prison term from time served to two years and five months.

Under the law, federal judges can amend sentences within seven business days that result from ''arithmetic, technical, or other clear error.''

In Gholikhan's case, prosecutor Michael Walleisa alerted Cohn last week that both sides had calculated Gholikhan's recommended sentence using the wrong federal sentencing guideline. The correct sentencing range should have been 30 to 37 months, Walleisa said.

He asserted in a legal brief that a sentence of time served was far too light a punishment for ''a national security offense that involved trade with a state sponsor of terror.''

''Her crime is serious and warrants an appropriately severe sentence,'' Walleisa wrote.

William Barzee, Gholikhan's attorney, called the resentencing unfair and un-American, saying after the hearing that his client feels like she's back in Iran.

''I don't think it's fair to (agree on a sentence) and have someone plead guilty and then come back and ask the court for a do-over,'' Barzee said in court Tuesday.

Cohn agreed with Walleisa that the sentence should be recalculated using the correct guideline provision. He reduced the sentence from 30 months to 29 because Gholikhan spent one month in an Austrian prison on related charges.

In light of the new sentence, Barzee said he would likely seek to withdraw Gholikhan's guilty plea and go to trial. U.S. Attorney Alex Acosta declined to comment.

Advisory sentences for federal crimes are calculated using a highly technical set of rules, known as guidelines. However, the guidelines are not mandatory and judges may deviate from them.

Jonathan Rosenthal, a Fort Lauderdale defense lawyer who teaches sentencing at Nova Southeastern University, said he found a description of Gholikhan's resentencing ''troubling'' because the guidelines are only one factor judges should consider.

''I don't understand how on Monday a sentence of four-and-a-half months is reasonable, but on Tuesday, all of a sudden, that sentence is no longer reasonable,'' Rosenthal said. ''Judges are not supposed to give guidelines any undue weight.''

Gholikhan was arrested with her ex-husband, Mahmoud Seif, in Austria in November 2004 after the pair allegedly took part in negotiations to illegally purchase Generation III military night vision goggles for the Iranian government.

In 2005, a federal grand jury in Fort Lauderdale indicted Gholikhan and Seif, who had since been released from Austrian custody. However, efforts to extradite them to the United States failed.

Aware of the international warrant for her arrest, Gholikhan agreed to come to the United States in December to face the charges. The case is being prosecuted in Broward County because the agents who conducted the investigation were based in South Florida.

On April 25, Gholikhan pleaded guilty to one conspiracy count and admitted she served as a translator at the Vienna meeting. She asked to be sentenced immediately and received time served.

Four days later, Walleisa asked for the resentencing hearing, saying Gholikhan's initial sentencing was so rushed he did not have time to double check the calculation provided by probation officers.

''I am not casting blame,'' Walleisa said in court Tuesday. ''I'm saying there was an error and we're here to fix that error.''

That explanation was tough to accept for Belghis Rovshan, Gholikhan's mother. In an e-mail from Tehran, Rovshan said she was confused by the events in her daughter's case.

''If there is a verdict for her and she is ordered to be released, how can the verdict be changed so suddenly!!!!!!!!!'' she wrote.