TEHRAN (Reuters) - An American woman who was freed after more than a year in an Iranian jail on suspicion of spying has been summoned back to attend trial, the official IRNA news agency reported Monday.

Sarah Shourd, 32, was arrested in July 2009 along with two male friends, Shane Bauer and Josh Fattal who are still in jail in Iran.

Shourd, who may opt to not return, a move which would delay any trial of Bauer and Fattal, said the trio were hiking in the mountains area of Iraq near the Iranian border and never intended to cross into Iran.

A trial set for last November was postponed, according to a judiciary spokesman, because of Shourd's absence.

"Sarah Shourd ... has been summoned by the Revolutionary Court to be present at next trial session," judiciary spokesman Gholamhosssein Mohseni-Ejei was quoted as saying Monday. The trial is set for February 6.

Shourd was released on $500,000 bail in September on humanitarian grounds and returned to the United States.

Under Iran's Islamic law, espionage can be punished by execution.

"The hearing will be held on scheduled date unless in some exceptional cases such as their lawyers' formal requests," Ejei said.

The case has further complicated relations between Iran and the United States which have had no diplomatic relations since the 1979 Islamic Revolution.

Washington has headed a global campaign to tighten sanctions on Tehran which it accuses of seeking nuclear weapons. Iran says its nuclear program is peaceful, aimed at generating electricity.