BAGHDAD, Iraq (CNN) -- Three American tourists are believed to be in Iranian custody after they may have strayed across the border from Iraq during a mountain hike, Kurdish officials said Friday.
Four Americans -- two of them students in Syria -- traveled from Syria to Turkey and then into Kurdistan in northern Iraq, arriving at Irbil on Tuesday, according to Peshrow Ahmed, spokesman for the security manager of Sulaimaniya, where they arrived Thursday after driving from Irbil.
All four spent the night at the Nirwan Hotel, according to the owner of the facility.
Three of the group left early Friday in a taxi for Ahmed Awa near Iraq's border with Iran, planning to hike in the mountains there, Ahmed said. The fourth member of the group was ill and stayed behind.
The taxi driver dropped the three off near the border and returned to town, he said.
Ahmed Awa police spotted the hikers at one point on Friday, Ahmed said, and warned them that they were near the Iranian border -- which is not marked in the area -- and that they should be careful.
The group was in contact with their companion in Sulaimaniya until about 1:30 p.m. Friday, when they reported they were "surrounded by Iranian soldiers," Ahmed said. No further communication was received.
Officials in Sulaimaniya are meeting to devise a strategy to bring the hikers home safely, Ahmed said.
State Department spokesman Robert Wood said the U.S. Embassy "is aware of the reports and is investigating. We are using all available means to determine the facts in this case."
Mudhafer Mohammed, owner of the Nirwan Hotel, said the hikers said they had come to the area because they heard it was safe, saying they were considering a trip to Ahmed Awa. But, he said, he advised them against it.
"I warned them many times," Mohammed said.
"When they told me that they are planning to go to Ahmed Awa, I told them, 'Don't go there because it is unsafe for you because you're American and Ahmed Awa is very close to the Iranian border,'" he said.
The fourth American who had stayed behind left the hotel about 4:30 p.m., Mohammed said, asking him to take care of their luggage and saying he would not return. Later, he said, Sulaimaniya security forces took the luggage from the hotel.
CNN's Mohammed Tawfeeq and Yousif Bassil contributed to this report.