A Saudi court on Tuesday sentenced 15 people to death for spying for Iran, the Saudi-owned Al-Arabiya television reported.
The 15 were among 32 people – 30 Saudis, an Iranian and an Afghan – who were detained in 2013 for allegedly spying for Iran.
The suspects were accused of forming a cell in collaboration with the Iranian intelligence service with a view to passing on secret Saudi information to Tehran.
No details are yet available about the trial of the remaining 17 defendants.
Tuesday’s verdict is still subject to appeal.
Tension has soared between Sunni-led Saudi Arabia and Shiite Iran since Riyadh cut its diplomatic ties with Tehran earlier this year after two of its diplomatic missions in Iran were attacked by Iranian protesters following the execution by the Saudi authorities of a prominent Shia cleric.