TEHRAN, Iran -- Iran confirmed that an Iranian-American businessman and his 81-year-old father have lost an appeal over their 10-year prison sentences.

The semi-official ISNA news agency on Sunday quoted Tehran prosecutor Abbas Jafari Dowlatabadi as confirming that Siamak and Baquer Namazi lost their appeals. The Associated Press reported the development last week, citing their lawyer.

"I condemn in no uncertain terms the cruel and unjust decision of the Tehran Appeals Court," their lawyer, Jared Genser, said last week. "The Namazis are innocent of the charges on which they were convicted and they are prisoners of conscious, detained in Iran because they are American citizens.

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The ISNA report also provided Iran's first acknowledgment that Nizar Zakka, a Lebanese man who is a permanent U.S. resident, has also lost his appeal.

Zakka advocates for internet freedom and has done work for the U.S. government. He was sentenced to 10 years last year on espionage-related charges.

The Namazis are among a number of dual nationals held in Iran after the 2015 nuclear deal. Analysts believe hard-liners use such detainees to undermine moderates.

In the wake of the 2015 nuclear accord, Iran freed detained Washington Post journalist Jason Rezaian and three other Iranian-Americans in exchange for pardons or charges being dropped against seven Iranians. That deal also saw the U.S. make a $400 million cash delivery to Iran.

Analysts and family members of those detained in Iran have suggested Iran wants to negotiate another, similar deal with the West. "The signal has been sent very, very clearly that this is what they want to do," Genser said.