Iranian border guards have arrested an American woman on suspicion of spying after she entered the country illegally by land, a semi-official news agency reported on Thursday. The Fars news agency said an "informed source" had confirmed a report earlier in the day in the daily Iran which said the woman had entered from Armenia and was detained by customs guards in the town of Nordouz in northwestern Iran . An espionage device was found in her teeth, according to the Iran daily, which is not known for carrying accurate reports. "She was arrested about one week ago," Fars quoted its source as saying. Iranian officials were not immediately available for comment. The Iran daily named the 55-year-old woman as Hall Talayan but did not say when she was detained.