From the Associated Press:

SULAIMANIYAH, Iraq – The U.S. State Department says it’s investigating reports that three Americans have been detained by Iranians after wandering near the border in the self-ruled Kurdish region in northern Iraq.
Two Kurdish officials say the three Americans apparently were arrested after entering Iranian territory without permission.
One security official says the missing Americans were tourists on an outing.
The official says the three contacted a colleague Friday and said “they had mistakenly entered Iranian territory and troops surrounded them.”
The officials spoke on condition of anonymity because they weren’t authorized to release the information.
State Department spokesman Robert Wood says the U.S. Embassy in Baghdad is “aware of the report and is investigating.”

I’ve been to the springs at Ahmadawa and, while the border is not well marked, it would be difficult to stumble across into Iranian territory.

Two relevant questions would be:

(1) Who were the Americans? (Journalists? Students? Academics? Contractors? Businessmen?)

(2) Did they stumble across the border or were they grabbed? Whatever was the case, the Kurdish authorities would describe it as the former, an accident.