Sarah Shourd has been held by Iran for more than a year; her mother says she is suffering poor health [Epa]

Iran has announced it will free Sarah Shourd, one of the three Americans it has held in prison for more than a year on accusations of spying.

An Iranian government official said on Thursday that Shourd will be released as an act of clemency to mark the end of the Muslim holy month of Ramadan.

Shourd, along with Shane Bauer and Josh Fattal, were arrested in July 2009 after straying into Iranian territory from Iraq. The three said that they became lost on a hike in Iraqi Kurdistan. US authorities insist that they are innocent and say they should be released immediately.

Bak Sahraei, the second counselor of Iran's UN mission, sent an e-mail confirming the release of Shourd, following up on an earlier text message from the culture ministry telling reporters to come to a Tehran hotel on Saturday morning to witness the release.

In the brief text message, the Iranian Ministry of Culture and Islamic Guidance announced the "freedom of one of the American detainees on Saturday 20th of (Iranian month of) Shahrivar at 9:00 (0430 GMT) at Hotel Esteghal" in the capital, Tehran.

Medical problems

The 31-year-old Shourd has told her mother that she is suffering from serious medical problems, including a breast lump and precancerous cervical cells.

The US state department said it was aware of reports that one of the prisoners would be released, but could not confirm them. America has no official presence in Iran, and the official said that the US government had heard nothing from the Swiss embassy in Tehran, which represents US interests in the country.

The hotel named in the text message is where the three Americans' mothers were allowed to visit them in May on a high-profile trip to Iran. In a joint statement, the mothers of the three prisoners said that they were hoping the reports were true.

"We have seen the news reports and are urgently seeking further information. We hope and pray that the reports are true and that this signals the end of all three of our children's long and difficult detention. 

"Shane, Sarah and Josh are all innocent and we continue to call for their immediate release, so that they can return home together and be reunited with our families."

'Unjust detention'

Their detention has added further strain to the already fractious relationship between Iran and the US, with Iranian leaders repeatedly attempting to link their fate to that of several Iranians being held by US authorities.

Barack Obama, the US president, and Hillary Clinton, the secretary of state, have both called for the release of the hikers over the past year.  Obama said the trio were "simply open-minded and adventurous young people who represent the best of America, and of the human spirit".

"I call on the Iranian government to immediately release Sarah, Shane and Josh," he said, adding that their "unjust detention has nothing to do with the issues that continue to divide the United States and the international community from the Iranian government."

Ghanbar Naderi, a journalist for the Iran Daily newspaper, said that the other prisoners would be released shortly. "The female prisoner is going to be released," he said. "I can assure you that the other two will also be released on compassionate grounds."

He insisted that there had been no deal between the US and Iranian governments on the fate of the hikers.

"There is no backroom deal," he said. "Of course the government listens to international opinion."

Source: Al Jazeera and agencies