TEHRAN, Iran — Iranian authorities have detained a 55-year-old American woman on spying charges, local media reported Thursday.

The state-owned newspaper IRAN said the woman had spying equipment hidden on her body when customs authorities detained her in the border town of Nordouz, 370 miles (600 kilometers) northwest of the capital Tehran. The report said she arrived in Iran from neighboring Armenia without a visa.

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 and officials could not be reached.

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

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

The U.S. has dismissed the spying charges. It says the three are innocent hikers and has repeatedly called for their release. The Americans’ 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 on $500,000 bail. 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.