ROME -- The Italian president granted partial clemency late Tuesday to an American ex-CIA agent on the eve of her expected extradition from Portugal to serve a prison sentence for her alleged role in the kidnapping of a Muslim cleric.

The presidential palace said President Sergio Mattarella had shaved one year off Sabrina de Sousa’s four-year sentence for her role in the abduction of the cleric, Osama Moustafa Hassan Nas. Also known as Abu Omar, he was kidnapped from a Milan street in February 2003.

The kidnapping was carried out under the United States’ “extraordinary rendition” anti-terrorism program, which was launched after the September 11, 2001 attacks. The program saw suspects kidnapped and transferred to centers abroad, where they were interrogated and often tortured.

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De Sousa denied involvement.

In this file photo taken on April 11, 2007, Egyptian cleric Osama Hassan Mustafa Nasr, known as Abu Omar, was allegedly kidnapped by CIA agents off the streets of an Italian city and taken to Egypt where he said he was tortured. Amr Nabil/AP

De Sousa, who has dual U.S.-Portuguese citizenship, had been due to be flown from Lisbon to Milan on Wednesday to start serving her sentence. The palace noted that because her sentence was reduced to three years, she can serve out the remainder of her term outside prison, although it was unclear if she would be able to do that in Portugal.

In evaluating de Sousa’s request for clemency, Mattarella took into account “that the United States has interrupted the practice of extraordinary renditions,” a reference to the Obama administration’s decision to halt the program.

Mattarella and his predecessor cited the same circumstances in previously granting clemency to other defendants in the case. She was one of 26 Americans who were tried and convicted in absentia for the cleric’s kidnapping.

Her lawyer in Italy couldn’t immediately be reached for comment.

Italian military intelligence officers also were convicted in the abduction, but the nation’s top criminal court ultimately threw out those convictions, ruling that the cases against them couldn’t be prosecuted due to state secrecy.

Italy was the first country to prosecute U.S. intelligence agents for roles in the rendition program.

De Sousa was detained on an international warrant at the Lisbon airport in October 2015 while en route to India to visit her mother. She has said she had been living in Portugal and intended to settle there.

She repeatedly fought her extradition and lost several appeals after her arrest. She had argued she was never officially informed of the Italian court conviction and could not use confidential U.S. government information to defend herself.