Image copyright AFP Image caption Computer screens in Bangladesh on Thursday displayed off-line messages

At least eight popular Bangladeshi websites used by bloggers have been blacked out in protest over the arrests this week of four online writers.

Those being held have been accused of hurting the religious sentiments of the country's Muslim majority.

The government has been accused by liberals of appeasing Islamists calling for tough blasphemy laws.

Hardliners want those they perceive to be anti-Islamic bloggers to face the death penalty.

But liberals say that bloggers' freedom of speech must be preserved. The sites are mostly run by individuals or small teams.

'Bullied'

"Bangla Blogosphere begins blackout in protest against harassing and cracking down on bloggers," reads a notice on the home pages of one of the protesting sites inaccessible fro 24 hours from noon (0700 GMT) on Thursday.

Detectives on Wednesday arrested blogger Asif Mohiuddin, who was attacked in January following alleged postings on the internet suspected of being derogatory to Islam and the Prophet Muhammad.

Mr Mohiuddin was remanded in custody by a court on on Thursday for three days to enable police to question him. His blog is suspended.

His arrest came a day after police arrested three other bloggers in Dhaka facing similar allegations.

In February blogger Ahmed Rajib Haider was killed outside his home for allegedly insulting Islam.

Critics say that the authorities have been bullied into carrying out the arrests following threats from radical Islamist organisations.

They have threatened to unleash anarchy if "atheist bloggers are not hanged".

Dhaka Metropolitan Police Deputy Commissioner Molla Nazrul Islam told local media that Mr Mohiuddin and other bloggers face charges of "instigating negative elements against Islam to create anarchy".

The issue of blogging became an issue in Bangladesh after a group of online activists took to the streets of Dhaka in February to demand the death penalty for Jamaat-e-Islami leader Abdul Kader Mullah. He was sentenced to life in prison for crimes committed during the country's 1971 war of liberation from Pakistan.

In recent weeks a group of bloggers, including Mr Haider, had launched mass protests demanding his execution and a ban on Jamaat-e-Islami, the country's largest Islamist party.

Jamaat denies being involved in war crimes and says the tribunal is part of a government vendetta against the party.