Another girl who 'liked' the comment was also arrested.

The duo were booked under Section 295 (a) of the IPC (for hurting religious sentiments ) and Section 64 (a) of the Information Technology Act, 2000. Though the girl withdrew her comment and apologized, a mob of some 2,000 Shiv Sena workers attacked and ransacked her uncle's orthopaedic clinic at Palghar, north of Mumbai.

Both the girls have been released on bail within hours, according to media reports.

The 21-year-old arrested for her Facebook post was among many who aired opinions on social networking sites.

"Her comment said people like Thackeray are born and die daily and one should not observe a 'bandh' (city shutdown) for that," Police Inspector Uttam Sonawane told the Mumbai Mirror.

Despite widespread concerns, there were no reports of unrest in Mumbai itself on the day of Bal Thackeray's crematon.

In recent months, the country has shown sensitivity to criticism of its politicians, sparking criticism in turn from freedom of speech campaigners.

In September, campaigners were outraged by the arrest in Mumbai on charges of sedition of a cartoonist for his anti-corruption drawings. The charges were later dropped.