A Saudi Interior Ministry official, Maj. Gen. Mansour Turki, said popular blogger Fouad Farhan had been detained and was being questioned.
The Saudi English daily Arab News said Farhan had "violated non-security regulations."
Farhan is one of the few bloggers who uses his real name. His blog headline reads: "Searching for freedom, dignity, justice, equality, shura and all the rest of lost Islamic values." Shura is Arabic for public consultation.