(CNN) -- An Armenian security agency cast more doubt Friday on media reports an American woman was arrested for spying after she entered Iran from Armenia.
Commenting on the reports that a U.S. citizen named Hall Talayan crossed the border, Artsvin Bagramian, head of Armenia's National Security Service press center, said that a person with that name never entered Armenia and thus neither left the country.
Citing Iranian authorities, the semi-official Fars News Agency reported Thursday that Iranian customs officials arrested the 55-year-old American woman on charges of illegal entry and espionage.
They said Talayan entered Iran from Armenia without a visa and security forces discovered "'espionage devices,' such as a microphone implanted in her teeth," Fars reported.
Citing an informed Iranian official, Fars said the woman asked authorities not to return her to Armenia because she feared for her life there.
She was detained in Nordouz, a border town in northwestern Iran, Fars reported.
Other media outlets also have reported the arrest.
But Al-Alam TV, an official Iranian news outlet, cited an informed source in Tehran who said the woman is in Armenia and didn't enter Iran. The outlet reported that the woman was denied entry into the country because she did not have an entry visa.
The U.S. State Department, noting the conflicting reports, is trying to find out what happened.
Secretary of State Hillary Clinton said on Thursday the United States has asked Switzerland "to please obtain as much information as possible as soon as possible to report to us whatever facts they can determine."
Iran and the United States do not have diplomatic relations, and Switzerland represents U.S. interests in Tehran.
In July 2009, three Americans were detained in Iran for spying after they allegedly strayed across an unmarked border while hiking in Iraq's Kurdistan.
One of them, Sarah Shourd, was released from an Iranian prison last September on humanitarian grounds. Fellow hikers Josh Fattal and Shane Bauer are still in prison.
Two German journalists, identified only as a reporter and photojournalist, were arrested in Iran in October and charged with espionage after they interviewed the son and lawyer of Sakineh Mohammadi Ashtiani, a woman who was convicted of adultery in 2006 and sentenced to death by stoning.
CNN's Ivan Watson contributed to this report