Raja Petra was arrested under a law that allows detention without trial
A prominent anti-government internet campaigner has been arrested in Malaysia, amid a crackdown on dissent.
Raja Petra Kamarudin was held under the majority Muslim country's controversial Internal Security Act, which allows indefinite detention without trial.
He was accused of posting an article that insulted Islam.
His arrest comes a day after the country's army chief warned people not to make remarks that could damage race relations.
General Abdul Aziz Zainal called for "stern action" to be taken against anyone stoking racial tension in the country.
Raja Petra was detained by police at his home near Kuala Lumpur, two weeks after his anti-government website Malaysia Today was closed down.
Interior Minister Syed Hamid Albar said he had been arrested because his writings posed a threat to national security, local media reported.
Independent online news outlets and blogs flourish in Malaysia, says the BBC's Robin Brant in Kuala Lumpur, and Raja Petra had been a constant thorn in the government's side before his arrest.
Earlier this year, he wrote a piece suggesting Najib Razak, Malaysia's deputy prime minister, may have been linked to the murder of a Mongolian model - a suggestion Mr Razak fiercely denied.
The blogger went into hiding earlier this week, but told the BBC at the time that he did not fear detention.
"I just want to make sure that for the next 10 days or so that i am going to be available to help in the dissemination of material that is going to be greatly required," he said.
The crackdown on dissent comes amid a race row that has threatened to engulf the government, our correspondent says.
Prime Minister Abdullah Ahmad Badawi had earlier suspended a member of the governing party who had described Malaysia's ethnic Chinese and Indians as "squatters".
Two newspapers have been put under investigation by the Interior Ministry for their reporting of the row.