Shiv Sena supporters brought chaos in some areas
Police in India's Maharashtra state are on high alert following sporadic incidents of violence in the capital, Mumbai (Bombay), the authorities say.
Tensions are running high after a statue of the late wife of right-wing Shiv Sena leader Bal Thackeray was found to have been vandalised.
Shiv Sena followers went on the rampage in some parts of the city.
Some political opponents say the party is using the incident to try to revive flagging political fortunes.
It is not clear who defaced the statue of Meenatai, Mr Thackeray's late wife, but anger quickly spilled onto the streets.
Shiv Sena supporters torched at least one bus and forced shops to shut in some areas.
A senior Shiv Sena leader and former speaker of the Indian parliament, Manohar Joshi, described the act of vandalism as against Hindus and Hinduism. He said it was natural for Shiv Sena followers to feel provoked.
Some Shiv Sena leaders alleged that followers of the regional Samajwadi Party were behind the act of vandalism.
The Samajwadi Party has not yet reacted to the allegation.
The Maharashtra government has asked police to be vigilant across the state.