"This 34-year-old woman who intended to enter Iran at the Norduz terminal on January 5 left Iran's borders after her situation became clear and legal procedures were followed," IRIB quoted an unnamed "high ranking security official" as saying.
Conflicting news articles had suggested that the woman was either American or was suspected of working for U.S. intelligence, but the official quoted by IRIB denied reports she had been filming the border area.
Adding to the confusion, IRIB said she had been held at Norduz, on Iran's border with its northern neighbor Armenia, whereas other news agencies said she had tried to enter at Jolfa, some 50 km (30 miles) to the west, on the border with Azerbaijan.
IRIB said the woman was seeking an Iranian visa and never entered Iranian territory. She was denied entry and returned to Armenia on Saturday, it said.
The news comes at a time of high tension between Tehran and Washington, which have been in a long-running dispute over Iran's nuclear programme.
The two countries have had no diplomatic relations since Iran's 1979 Islamic Revolution but both will be represented at talks in Istanbul later this month which Western countries hope will address the nuclear stand-off.
Three Americans -- two men and a woman -- were arrested in July 2009 near the Iran-Iraq border on suspicion of spying. The woman, Sarah Shourd, was released on bail a of $500,000 in September and returned to the United States. She has said the three of them strayed across the border while hiking in Iraq.
Her two companions remain in jail awaiting trial, which was postponed in November due to Shourd's absence.
