Secretary of State Hillary Rodham Clinton yesterday appealed to Iran for information on three Americans believed to have been arrested after entering Iran by mistake while on a hiking trip in neighboring Iraq.

"As of a few hours ago, we did not yet have official confirmation that the Iranian government or an instrument of the Iranian government were holding the three missing Americans," Clinton told reporters in Washington. "We asked our Swiss partners . . . to please pursue our inquiries."

The three have been identified by friends and relatives as Joshua Fattal, who grew up in Elkins Park; Shane Bauer, a freelance journalist and photographer; and Sarah Shourd, a writer for online publications, including Brave New Traveler.

A Kurdish official in Iraq has said the three contacted a colleague to say they had entered Iran by mistake on Friday and were surrounded by troops. Iran's state television said the three were arrested after they did not heed warnings from Iranian border guards.

State Department spokesman P.J. Crowley told reporters that the Swiss ambassador in Tehran met with Iranian officials Sunday. The Iranians told the Swiss that they could not confirm the detention of the Americans, Crowley said. Switzerland represents U.S. interests in Iran.

Fattal's father, Jacob, told the Associated Press yesterday that he did not have any updates from the State Department about his son. "All we care about is the well-being of Josh and his two hiker friends," he said.

Joshua Fattal, 27, a 2000 graduate of Cheltenham High School, spent three years recently living with Aprovecho, a group dedicated to sustainable farming, near Cottage Grove, Ore. He lived with about nine others and worked as the group's intern coordinator before leaving about eight months ago, according to Jason Brown, who now holds Fattal's job.

From January to June, Fattal traveled overseas as a teaching assistant with the Boston-based International Honors Program, visiting Switzerland, India, South Africa, and China on a global ecology program. Fattal was in the program during college, said Joan Tiffany, president of the honors program.

"He's a very thoughtful, caring person, soft-spoken, smart, bright. Has lots of travel experience, and is someone that I would expect to be an experienced camper," Tiffany said.

Bauer and Shourd had been living in the San Francisco Bay area.

Bauer, a freelance writer, planned to spend a week covering the Kurdish elections in Iraq.

In an e-mail, Bauer told Pacific News Service executive director Sandy Close that he wanted to "feel out the situation there and get some ideas for deeper stories."

Close said Bauer had gone backpacking with his girlfriend Shourd in a popular tourist area. Close said she doubted that Bauer would have deliberately tried to enter Iran.

"He did not express any interest in going to Iran. He did not speak Farsi, his passion was Arabic," she said.

Bauer's mother, Cindy Hickey of Pine City, Minn., said she was concerned for the group's safety.

Ross Borden, founder of Matador, an online travel magazine that includes Brave New Traveler, described Shourd as "very professional."

"She's obviously a professional traveler, as you can see by her latest adventure, going hiking in Iraq," he said. "Not many people go hiking in Iraq."

A fourth member of the group, Shon Meckfessel, did not go on the hike because he was sick.