The American-born Iran state TV broadcaster detained by the FBI for 10 days for unknown reasons will protest her “illegal detention” Friday in Washington, D.C., her family said after she was released Wednesday.

The announcement Thursday surrounding Marzieh Hashemi, an anchorwoman from Press TV, comes as questions remain over why she was tracked down and arrested by federal agents at a St. Louis airport on Jan. 13.

Hashemi, who was held as a material witness, appeared at least twice before a U.S. District judge in Washington, and court papers said she would be released immediately after her testimony before a grand jury. Court documents did not include details on the criminal case in which she was summoned to speak about.

“Marzieh and her family will not allow this to be swept under the carpet. They still have serious grievances and want answers as to how this was allowed to happen,” her family said in a statement published by Press TV.

“Marzieh Hashemi will be remaining in Washington, D.C. for the protest on Friday and calls for all cities across the world to keep their protest,” the statement added.

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A spokesperson for Hashemi told Fox News that rallies would be held in other U.S. cities including New York City, Los Angeles and Houston. The spokesperson did not respond to a question about why Hashemi was detained.

Earlier Wednesday, dozens of activists protested outside the federal courthouse in Washington, where Hashemi was scheduled to appear before the grand jury. They held signs and chanted, "Free, free, Marzieh!" and "Shame, shame, USA!"

An attorney with the American-Arab Anti-Discrimination Committee confirmed her release later that night.

Hashemi, 59, is an American citizen and was born Melanie Franklin. She lives in Tehran and comes back to the United States about once a year to see her family, usually scheduling documentary work in the U.S., her son told the Associated Press.

Iran has repeatedly cried foul over her detention, although the Islamic Republic has faced criticism of their own for holding onto U.S. citizens overseas, some who have been languishing in prisons for years.

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Not even 24 hours after Hashemi’s release, Amnesty International tore into the Iranian regime, issuing a report stating that more than 7,000 people were arrested there last year -- including dozens of journalists -- in what they called a "shameless campaign of repression.”

Iran was said to have recently sentenced prominent whistleblower journalist Yashar Soltani to five years in prison after he penned a series of exposes alleging massive corruption in land deals tied to Tehran's former mayor.

Meanwhile, Iranian state TV continues to face criticism for airing statements from detainees made under duress, including two recent ones from labor activists Esmail Bakhshi and Sepideh Gholian who allegedly faced torture. Authorities detained both of them again this week.

The Amnesty report said that among those arrested in 2018 were protesters, students, journalists, environmental activists, workers and human rights defenders. Some 50 detainees were media workers, of whom at least 20 "were sentenced to harsh prison or flogging sentences after unfair trials," the report said.

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"2018 will go down in history as a 'year of shame' for Iran," said Philip Luther, Amnesty's Middle East and North Africa research and advocacy director. "Iran's authorities sought to stifle any sign of dissent by stepping up their crackdown on the rights to freedom of expression, association and peaceful assembly and carrying out mass arrests of protesters."

The Associated Press contributed to this report.