(CNN) -- Relatives of three American hikers detained in Iran are still waiting for news about their loved ones.
Sarah Shourd, seen in a family photo, is one of three American hikers detained in Iran.
More than a month has passed since Iranian authorities detained Shane Bauer, Sarah Shourd and Josh Fattal after they strayed into Iran -- by accident, a friend and relatives say -- while hiking in northern Iraq.
Their relatives in the United States have heard nothing about their fate, they said Tuesday on CNN's "American Morning."
"We know they're being detained in Iran. Beyond that, we haven't heard anything from them," said Nora Shourd, the mother of Sarah Shourd.
The waiting takes a toll.
"It's just very difficult," said Alex Fattal, Josh Fattal's brother. "Each day feels like a month.
"It's a long time -- each hour, each day -- to not know under what conditions Josh, Shane and Sarah are being held and if they're OK."
The hikers' relatives said they hope the Iranian government lets Swiss diplomats visit the hikers. The Swiss government represents U.S. interests in Iran. The U.S. and Iran have not had diplomatic relations since the American hostage crisis of 1979.
The three Americans entered northern Iraq from Turkey on July 28 with plans for five days of hiking. Bauer and Shourd had been living in Damascus, Syria; Fattal was visiting. They set out to hike in northern Iraq's Kurdistan region with a fourth friend, Shon Meckfessel.
Meckfessel ended up staying behind at their hotel on July 31, the day the three went missing, because he had a cold, he has said. He has said his friends did not know they were near the border and made "a simple and regrettable mistake" by crossing into Iran.
Relatives have said the three "accidentally strayed into Iran across an unmarked border."
Authorities in Iran charged the three with illegally entering the country, according to the semi-official Fars News Agency.
Relatives and friends have set up a Web site -- http://www.freethehikers.org/index.html -- to help call attention to the detained hikers.
The recent release of two detained American journalists in North Korea, they told CNN on Tuesday, offers them a reason to feel encouraged.
"It does make us hopeful, of course," Alex Fattal said.