GENEVA (Reuters) - A U.S.-born anchor for Iran’s state-run Press TV arrived in Iran on Wednesday after 10 days of detention in the United States, Press TV reported, after U.S. authorities said she had testified as a material witness in an undisclosed federal investigation.

The anchor, Marzieh Hashemi, was freed on Thursday.

Hashemi’s detention added to the tension that has grown between Iran and the United States since U.S. President Donald Trump’s decision last May to pull out of an international nuclear deal and reimpose sanctions on Tehran.

“It’s very good to be home,” Hashemi said, on a visit to the Press TV office following her arrival in Tehran.

Hashemi said she feared she would be detained again on her flight leaving the United States from Denver to Frankfurt, adding: “I was not comfortable as long as I was over U.S. airspace.

“I was thinking they can reroute the plane and bring it down in Washington. It sounds like a movie but I lived through that movie so I know that anything is possible.”

Hashemi, 59, was arrested by the FBI at St. Louis Lambert International Airport and transferred to a detention center in Washington D.C., where she was held for two days before managing to contact her family, Press TV said.

Press TV said she was mistreated in jail because her hijab was removed and she was offered non-halal food, or food not permissible under Islamic law.

The channel aired live footage of her arrival at Tehran’s Imam Khomeini airport, where a crowd greeted her with flowers.

U.S. federal law allows the government to arrest and detain a witness if it can prove their testimony is material to a criminal proceeding and it cannot guarantee their presence through a subpoena.

The U.S. government has declined to disclose details of the criminal case in which Hashemi testified. However, a U.S. government source told Reuters it appeared that the grand jury was examining whether English-language Press TV is a propaganda outlet that failed to register with the Justice Department as an agent of a foreign government.

Hashemi was born Melanie Franklin in the United States and changed her name after converting to Islam. She received Iranian citizenship after marrying an Iranian.

She had traveled to the United States to visit her family, Press TV said.

Several Iranian dual nationals from Austria, Britain, Canada, France and the United States have been detained in Iran in the past few years on charges such as espionage and collaborating with hostile governments.