Two protesters have been killed in the violence
Two newspaper offices have been attacked in India's Karnataka state in unrest over an article allegedly written by the writer Taslima Nasreen.
Two Muslim protesters were killed in clashes with police after the article, which challenges the Muslim practice of veil wearing, appeared in local papers.
An unidentified group vandalised the office of the Kannada Prabha newspaper, which carried the article, police said.
Ms Nasreen has denied writing the article for the newspaper.
She said an article she had written had been translated into the Kannada language and "doctored" to malign her.
Ms Nasreen fled her native Bangladesh in 1994 after receiving death threats relating to a book she had written.
Muslims said her work was offensive to them. She left India in 2008 after further protests and went to live in Sweden.
The appearance of the article in the Kannada Prabha newspaper, whose offices were attacked by a mob on Tuesday night, triggered protests in the Shimoga and Hassan areas.
Police said a group of 10 masked men attempted to set the newspaper's office in Mangalore on fire after dousing the premises with petrol, but firemen extinguished it in time.
The police said the same group attacked another newspaper office in the area.
"The miscreants have been arrested. We have some clues about who was behind the attacks," senior police official Gopal Hosur said.
Separately, in Shimoga, incidents of stone throwing and arson were reported despite a continuing curfew in areas affected by the violence.
Police said two protesters were killed after they opened fire on Monday. About 50 people have been injured in the violence.
Police say Hindu groups joined the unrest in Shimoga and Hasan after Muslims took to the streets. About 50 arrests have been made in connection with the violence.
Several shops and vehicles have been set on fire in retaliatory attacks by Muslims and Hindus.