One of the three Americans jailed for more than a year in Iran will be released Saturday, Iranian government sources said Thursday.

The foreign press department of the culture ministry invited the media to the Esteqlal (former Hilton) hotel in northern Tehran for Saturday to cover the release of one of the three Americans.

It is not clear which one of the Americans would be released, but observers believe that it would be Sarah Shourd, who is reportedly ill.

Iranian authorities arrested Shourd, together with Shane Bauer and Josh Fattal, in July 2009 when they allegedly crossed an unmarked border into Iran while hiking in Iraq's Kurdistan region.

Iranian Intelligence Minister Heydar Moslehi said last month that the case of the three American hikers would be closed soon with a verdict to follow shortly.

The three hikers' mothers were allowed to visit them for the first time in May. But, despite raised hopes, there was no release on humanitarian grounds.

Tehran rejected a call by US President Barack Obama last month to release the three American hikers. Iranian officials said Obama would have no role in the legal process and his efforts for their release would remain futile.

The three hikers also face spying charges, but the Iranian foreign ministry said that the main charge against the three remained illegal entry into Iran. Espionage charges have not yet been fully confirmed and are still under investigation.