The case pertains to allegations that Khan had shared contents of a secret cable sent by the country's ambassador in Washington to the government in Islamabad.

Khan's party, the Pakistan Tehreek-e-Insaf (PTI), said both Khan and former foreign minister Shah Mehmood Qureshi had been sentenced to 10 years each by a special court.

It said the party would challenge the decision and called it a "sham case".

(Reporting by Gibran Peshimam; writing by Sakshi Dayal; editing by Sudipto Ganguly and Christian Schmollinger)