An American journalist jailed in Iran for allegedly spying for the US is vowing to remain on a hunger strike until she is freed even though she is "very weak," her father said Monday.

This undated photo released by the family of imprisoned Iranian-American shows journalist Roxana Saberi in Tehran, Iran. [Chinadaily.com.cn via agencies]

Roxana Saberi, who has been on a hunger strike for a week, was convicted more than a week of ago and sentenced to eight years in prison after a one-day trial behind closed doors.

Her parents said they brought her a bouquet of flowers on Sunday, her 32nd birthday, and were able to visit her again in Evin prison on Monday.

"Roxana is very weak and pale. She has been on a hunger strike for a week now," her father, Reza Saberi, told The Associated Press. "She is only drinking sweetened water to remain alive."

He said he tried to persuade his daughter to end her hunger strike but she refused. "She vowed to remain on hunger strike until she is freed," he said.

The United States has called the accusations against Roxana Saberi, a dual Iranian-American citizen who was born in the US and grew up in Fargo, North Dakota, baseless and demanded her release.

The case has been a source of tension between Washington and Tehran at a time when the Obama administration has said it wants to engage its longtime adversary.

Iran has released few details about the charges against Saberi. On Monday, Iran's Foreign Ministry spokesman said Saberi's supporters would be surprised if the judiciary made the evidence against her public.

"Should the judge decide to expose details, the revelations will definitely make some of her supporters inside and outside Iran think seriously about the case," Hasan Qashqavi told a press conference. He didn't elaborate or say what the evidence was against Saberi.

He warned the US not to make judgments or interfere with the case and stressed that Saberi was tried as an Iranian citizen.

"Saberi is treated as an Iranian national because all her documents including her passport and identification papers prove her Iranian identity. ... Her case has nothing to do with a foreign party," he said in a reference to the United States.

Saberi moved to Iran six years ago and worked as a freelance journalist for news organizations including National Public Radio and the British Broadcasting Corp. She received Iranian citizenship because her father was born in Iran.

Saberi's lawyer, Abdolsamad Khorramshahi, appealed the court's ruling on Saturday, days after Iran's judiciary spokesman said an Iranian appeals court would reconsider her verdict, an indication her sentence could be commuted.

Iran's judiciary chief has ordered a full investigation into the case, and President Mahmoud Ahmadinejad has urged Tehran's chief prosecutor to ensure Saberi be allowed a full defense during her appeal.

Saberi was arrested in late January and initially accused of working without press credentials. But earlier this month, an Iranian judge leveled the far more serious allegation of espionage.

The US broke off diplomatic relations with Iran after the 1979 Islamic revolution and the takeover of the US Embassy in Tehran by hard-line Iranian students. The Obama administration has said it is working with Swiss intermediaries who represent US interests in Iran to secure her release.

Saberi's parents have traveled to Iran from their home in Fargo in a bid to help win their daughter's release. Her father has said his daughter, who was Miss North Dakota in 1997, had been working on a book about the culture and people of Iran, and hoped to finish it and return to the United States this year.

(Chinadaily.com.cn via agencies April 28, 2009)