WASHINGTON -- Three Americans who were arrested by Iranian border guards in late July after crossing into Iran from neighboring Iraq have been charged with espionage, a top Iranian prosecutor said yesterday.

Abbas Jafari Dowlatabadi said an investigation is continuing, and that a "final decision" about their case would be announced soon, a state-run news agency reported, leaving it unclear whether Iran would go ahead with a formal trial on spying charges, which carry the death penalty.

The three -- Shane Bauer, Joshua Fattal and Sarah Shourd -- were hiking in the mountains of Iraq's northern Kurdish region on July 31 when, according to their families, they strayed across the border accidentally. Authorities in Tehran confirmed three days later that the three had been arrested, and an Iranian Arabic-language television network quoted police sources as saying they were "CIA agents."

President Mahmoud Ahmadinejad, asked about the case yesterday during a visit to Turkey, said he hoped that the Americans could persuade Iran's judiciary that they are not guilty of espionage, but he suggested that they deserve at least some punishment for entering the country illegally.

Mr. Bauer, 27, and Ms. Shourd, 31, are freelance journalists who were living together in Damascus, Syria, where Ms. Shourd also taught English and was studying Arabic, friends and relatives said. Mr. Fattal, 27, is a friend of Mr. Bauer's who was visiting the Middle East to explore his father's roots in Iraq, friends said.

All three graduated from the University of California at Berkeley.

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