An American linguistics student traveling in northern Iraq didn't go on an ill-fated hiking trip because he had a cold — a twist of fate that prevented him from mistakenly wandering into Iran where his three friends were reportedly detained.

The Swiss Embassy in Tehran was working Sunday to learn more about the Americans' fate through its contacts with the Iranian Foreign Ministry, spokeswoman Nadine Olivieri said. Switzerland represents U.S. interests in Iran.

Shon Meckfessel sat out the hike because he had a cold, his grandmother, Irene Meckfessel, told The Associated Press from her home in Carmichael, California. He called her Saturday from the American Embassy in Baghdad, she said.

The four had traveled to Turkey, then entered Iraq on Tuesday and traveled to Sulaimaniyah, according to the Kurdish regional government. On Thursday, one stayed behind while the other three took a taxi to the resort town of Ahmed Awaa, it added.

The regional government's statement said the three got lost during an excursion and were detained by Iranian authorities at the border.

The area where the three disappeared is a popular hiking destination known for a picturesque waterfall and rocky scenery as well as a thick growth of fruit and nut trees.

Camping equipment and two backpacks apparently belonging to the Americans were found in the area and it seemed they were hiking above the waterfall when they accidentally crossed the border, a Kurdish security official said, speaking on condition of anonymity because he wasn't authorized to release the information.

Shortly before their capture, the three contacted a fourth member — Meckfessel — to say they had entered Iran by mistake and were surrounded by troops, the official said.

Iran's state TV said the Americans were arrested after they did not heed warnings from Iranian border guards. It cited a "well-informed source" in the Interior Ministry.

One of the missing Americans has been identified by Kurdish authorities as Joshua Fattal. His mother, Laura Fattal of Elkins Park, Pennsylvania, issued a brief statement Sunday.

"My husband and I are only concerned about Josh" and the two others, she said.

Meckfessel and another of the missing hikers were both studying Arabic, said Irene Meckfessel, who raised her grandson. Shon Meckfessel had most recently studied at the University of Washington in Seattle.

"He's very much interested in people and languages and he's working on a Ph.D. in linguistics," she said.

In Iran, Swiss diplomats have asked for consular access to the Americans if their presence in Iran is confirmed, Olivieri told the AP. Switzerland has represented U.S. interests in Iran since American diplomats were taken hostage at the embassy in Tehran 30 years ago.

"Our embassy in Tehran is in contact with the Iranian Foreign Ministry and is trying to get a confirmation of the situation," she said.

The State Department, which requested the help, knows about Switzerland's efforts, said spokesman Robert Wood in Washington.