Saudi Arabia says it has uncovered a spy network.
The Saudis are known for being extra sensitive about outside interferences.
But this alleged spy cell is different.
Of the 18 people arrested, one is an Iranian citizen.
Another is Lebanese. The rest are members of Saudi Arabia's Shiite minority.
And Thursday, a spokesman for the Saudi Interior Ministry said they were all working for Iran.
Saudi journalist Ahmed al Omran is covering the intrigue on his blog, Riyadh Bureau.
He says the decision to point a finger at Iran was unexpected.