Indian media reported that Gurmeet Ram Rahim Singh’s followers set a vehicle alight just ahead of sentencing.
Violence after Friday’s verdict in Panchkula in northern Haryana state had killed some 38 people.
The self-styled holy man was found guilty of sexually assaulting two female followers and jailed for 10 years for each, to run consecutively.
There were initial reports of a 10-year sentence but his lawyers confirmed the sentencing was of consecutive, not concurrent, terms.
Prosecutors had called for a life sentence.
A lawyer for the victims said 50 women had come forward with allegations of rape and they would be seeking further investigation in the case.
“We believe there are at least 48 more victims who were sexually abused and who may have been killed or are too scared to come out and testify against Ram Rahim,” lawyer Utsav Singh Bains told AFP.
Ram Rahim Singh denies charges of murder in two cases due to be heard next month.
Following the sentencing, the chief minister of Haryana state, where Singh’s ashram is located, called an emergency meeting.
A curfew has already been imposed in several areas of Haryana and Punjab states, while the capital Delhi is on alert.
The army has been put on standby and police say they have been given “shoot on sight” orders in case of trouble.
Singh, 50, was not taken to court to hear his sentence. Instead, the judge who convicted him was flown to the prison in the town of Rohtak where Singh is being held.
Who is Gurmeet Ram Rahim Singh?
Controversial leader of the Dera Sacha Sauda sect, which claims to have 60 million followers around the world
Took over the sect – which describes itself as “a non-profit social welfare and spiritual organisation” – when he was 23
Performs at rock concerts, acts in films and even has his own line of food products
Known as “rockstar baba” and “guru of bling” because of his shiny, colourful clothes
Has been accused of mocking Sikh and Hindu figuresHas been investigated for murder and rape, charges he denies
Has been accused of forcing followers to undergo castration to “get closer to god”
The prison has been transformed into a fortress, with journalists banned within a 1.5km (one mile) radius.
Rohtak, in Haryana state, is also under police and military lockdown, the roads lined with barbed-wire barricades.
There is also heavy security outside Singh’s 1,000-acre compound in Sirsa, Haryana.
Thousands of his supporters are still believed to be inside the Dera Sacha Sauda sect headquarters, despite many opting to leave following a tense stand-off with soldiers.
The Dera’s Sirsa headquarters is a huge township that houses schools, a hospital and a cinema.
In his monthly radio address on Sunday, Prime Minister Narendra Modi said it was “natural to be worried” after days of violence which had briefly reached Delhi.
“Violence is not acceptable in the nation, in any form,” Mr Modi said.
“Those who take the law into their hands or take to violence will not be spared, whoever they are.”