Switzerland, which in the absence of US-Iranian diplomatic relations represents American interests in Iran, had been asked to help track them down, she added.
State Department spokesman P.J. Crowley told reporters that despite the lack of official confirmation there was no reason to doubt the Iranian state TV report.
The presumed detention of the US nationals comes as Washington seeks to increase pressure on Tehran over its nuclear program and amid political turmoil in Iran following President Mahmoud Ahmadinejad's disputed re-election.
Clinton's plea to Tehran for information regarding the missing Americans came as more details emerged about the trio.
The autonomous Kurdish government in northern Iraq, where the three Americans set off from, said it was in contact with Iranian and US officials in a bid to resolve the issue.
A Kurdish official identified the three as US backpackers and said they were arrested after having been warned on the Iraqi side not to hike in the mountain area because it is close to the border with Iran, which is not clearly marked.
Iraqi Kurd officials initially named them as Shane Bower, Sara Short and Joshua Steel and said a fourth American, Shaun Gabriel Maxwell, stayed behind in their hotel in the Kurdish region's second largest city of Sulaimaniyah.
US media reports Monday identified the missing trio as Shane Bauer, a freelance photojournalist, Sarah Shourd and Joshua Fattal, while the fourth member of the group was said to be Shon Meckfessel.
Bauer was described by New American Media (NAM), one of the US media outlets to which he contributes, as "a gifted writer and photographer" who was fluent in Arabic and interested in Arabic culture.
He travelled to the Middle East late last year, "to be a writer and tourist," NAM managing editor Annette Fuentes told AFP.
Shourd described herself as an English language teacher, writer and human rights activist in a pitch to Matador, an online travel-writing website which has published her work. She also left for the Middle East late in 2008.
Fattal reportedly left the non-profit organization Aprovecho, which promotes sustainable living, eight months ago to travel in the Middle East.
US officials have refused to reveal details of the three for privacy reasons.
White House spokesman Robert Gibbs echoed State Department remarks that the US government was working with Swiss diplomats to confirm reports about the three.
Asked whether the White House had a warning about the potential dangers of crossing borders, Gibbs said the message was "obviously to take great care in ensuring you know where you are."
Iranian-American reporter Roxana Saberi, who had been living and working in Iran, was sentenced earlier this year to eight years in prison for spying for the United States but was freed after having served 100 days in jail.
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State Department spokesman P.J. Crowley told reporters that despite the lack of official confirmation there was no reason to doubt the Iranian state TV report.
The presumed detention of the US nationals comes as Washington seeks to increase pressure on Tehran over its nuclear program and amid political turmoil in Iran following President Mahmoud Ahmadinejad's disputed re-election.
Clinton's plea to Tehran for information regarding the missing Americans came as more details emerged about the trio.
The autonomous Kurdish government in northern Iraq, where the three Americans set off from, said it was in contact with Iranian and US officials in a bid to resolve the issue.
A Kurdish official identified the three as US backpackers and said they were arrested after having been warned on the Iraqi side not to hike in the mountain area because it is close to the border with Iran, which is not clearly marked.
Iraqi Kurd officials initially named them as Shane Bower, Sara Short and Joshua Steel and said a fourth American, Shaun Gabriel Maxwell, stayed behind in their hotel in the Kurdish region's second largest city of Sulaimaniyah.
US media reports Monday identified the missing trio as Shane Bauer, a freelance photojournalist, Sarah Shourd and Joshua Fattal, while the fourth member of the group was said to be Shon Meckfessel.
Bauer was described by New American Media (NAM), one of the US media outlets to which he contributes, as "a gifted writer and photographer" who was fluent in Arabic and interested in Arabic culture.
He travelled to the Middle East late last year, "to be a writer and tourist," NAM managing editor Annette Fuentes told AFP.
Shourd described herself as an English language teacher, writer and human rights activist in a pitch to Matador, an online travel-writing website which has published her work. She also left for the Middle East late in 2008.
Fattal reportedly left the non-profit organization Aprovecho, which promotes sustainable living, eight months ago to travel in the Middle East.
US officials have refused to reveal details of the three for privacy reasons.
White House spokesman Robert Gibbs echoed State Department remarks that the US government was working with Swiss diplomats to confirm reports about the three.
Asked whether the White House had a warning about the potential dangers of crossing borders, Gibbs said the message was "obviously to take great care in ensuring you know where you are."
Iranian-American reporter Roxana Saberi, who had been living and working in Iran, was sentenced earlier this year to eight years in prison for spying for the United States but was freed after having served 100 days in jail.
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