There are conflicting reports as to whether an American woman has been detained by Iranian authorities on spying charges.

Iran's state television denies that a 55-year-old American woman has been detained by border guards despite an earlier report from a state-owned newspaper claiming Iranian authorities detained her on suspicion of spying.

"This woman tried to enter the country illegally but she was prevented from doing so," Iran's Arabic language television al-Alam quoted an unnamed source as saying, according to Reuters.

The daily IRAN said the woman had spying equipment hidden on her body when customs authorities detained her in the border town of Nordouz, 370 miles northwest of the capital Tehran. The report said the woman arrived in Iran from neighboring Armenia without a visa. It did not say when she was detained.

The paper identified the woman in Farsi as Hal Talaian and said she was found to have "a microphone" between her teeth. It did not say when she was detained.

But Iran's semiofficial Fars news agency quoted an unnamed official as saying the woman was taken into custody "about one week ago."

Armenian authorities had no immediate comment on the reported arrest. The U.S. Embassy in Armenia's capital Yerevan was closed for the Orthodox Christmas.

In Washington, State Department spokesman Mark Toner said U.S. officials have yet to confirm the reports. He said the U.S. was seeking more information through Swiss officials, who represent American interests in the Islamic Republic, and the U.S. Embassy in Armenia.

If the woman's arrest is confirmed, Talaian would be the fourth American Iran has arrested and accused of spying in less than two years.

In July 2009, Iran detained three Americans who were initially accused of crossing the border illegally from northern Iraq and later accused of spying.

The U.S. has dismissed the spying charges and says the three are innocent hikers. Their families have said if they crossed the border at all, it was inadvertent.

One of the three, Sarah Shourd, was released in September on compassionate grounds. Her fiance, Shane Bauer, and friend Josh Fattal remain in prison and could go on trial next month.

Iran has suggested in the past that the Americans in its custody could be traded for Iranians held in the U.S., raising concerns that the Americans are to be used as bargaining chips as the two countries face off over issues like Iran's disputed nuclear program.

The U.S. and its allies fear Iran aims to develop atomic weapons. Tehran denies the allegations, and says its nuclear program is for peaceful purposes.

The Associated Press contributed to this report.