Controversial blogger Raja Petra Kamaruddin has been detained under the Internal Security Act, said his wife Marina Lee Abdullah.
According to Marina, 10 police personnel came to their home in Sungai Buloh at about 1.10pm to arrest him.
When Malaysiakini contacted her at 1.25pm, the police personnel were still there.
On Sept 6, Home Minister Syed Hamid Albar had warned the 58-year old editor of popular news portal Malaysia Today he could be charged under the ISA for comments allegedly insulting Islam and Prophet Muhammad
Several religious groups - Malaysian Islamic Development Department (Jakim), Yayasan Dakwah Islamiah Malaysia (Yadim), Federal Territory Islamic Religious Council (Maiwp) and Federal Territory Religious Department (Jawi) - had lodged police reports against him.
The groups complained his comment in an article entitled "I Promise to be a good, non-hypocritical Muslim" allegedly used sentences that insulted Muslims.
Raja Petra, popularly known by his initials RPK, is also alleged to have allowed comments to appear on his website that degraded Islam and Prophet Muhammad in an article entitled "Not all Arabs are descendants of the Prophet
Meanwhile, his wife Marina said they had yet to appoint a lawyer to handle the matter.
This is the second time Raja Petra, a father of five and part of the Selangor royal family, has been detained under ISA, which allows for indefinite detention without trial.
His first arrest under the tough security law was on Apr 11, 2001. RPK was detained as part of a crackdown against reformasi activists in which nine others were also held. At that time he was webmaster for the now de-funct FreeAnwar.com
Raja Petra was released after 52 days in detention. However, six of the reformasi leaders were eventually sent to the Kamunting Detention Centre in Taiping where they were detained for two years.