Yahoo TV

STORY: Saadoun was greeted by his father, Taher Saadoun, and the media after landing in Casablanca.

Saadoun had been sentenced to death by Russia and found guilty of "mercenary activities and committing actions aimed at seizing power and overthrowing the constitutional order of the DPR" -- a sentence condemned by Ukraine and Britain.

Ten foreigners were freed on Wednesday (September 21) following mediation by Saudi Crown Prince Mohammed bin Salman, who has maintained close ties with Russian President Vladimir Putin.

The timing and size of the swap came as a surprise. Earlier in the day Putin had announced a partial troop mobilization in Russia in an apparent escalation of the conflict that began in February. Pro-Russian separatists had said last month that the Mariupol commanders would go on trial.