CAIRO (Reuters) - An Egyptian court sentenced one of the leading activists of the 2011 “Arab Spring” uprising to a one-year prison term on Wednesday after convicting him of spreading false news, a judicial source and a lawyer said.

Zyad Elelaimy, a prominent rights lawyer and former member of parliament already in detention since June last year over separate charges, was also fined 20,000 Egyptian pounds ($1,272) by a Cairo misdemeanor court on Tuesday, they added.

The court found Elelaimy guilty three years after a lawyer reported him to prosecutors citing an interview he had given to the BBC, his lawyer Ahmed Fawzi told Reuters.

Fawzi said the defense team had been unable to clarify in court which comments Elelaimy was being prosecuted for. The defense team has appealed against the sentence, and a hearing is due to be held on April 7, Fawzi added.

Amnesty International condemned the ruling as based on “unfounded charges” and called on Egyptian authorities to immediately release him.

“He is a prisoner of conscience, who has been swept up in Egypt’s ruthless purge of critics and opponents,” it added in a statement.

Elelaimy was one of the leading Egyptian activists during the 2011 popular revolts across the region that toppled long-serving autocrat Hosni Mubarak and several other Arab leaders. Mubarak died last month.

President Abdel Fattah al-Sisi - like Mubarak a former senior military officer - has overseen a crackdown on dissent that has targeted liberal opponents as well as the Islamists who briefly held power after the Arab Spring.

Tens of thousands of people have been detained, though Sisi has denied holding political prisoners. He and his backers say the measures are necessary to stabilize Egypt.

Elelaimy was detained with several others last June on charges including spreading false news and coordinating with a terrorist group - charges commonly used against protesters and political opposition figures.

Colleagues and activists said the arrests were aimed at preventing the formation of a secular coalition ahead of parliamentary elections due later this year.