An Indian court on Monday sentenced the controversial and hugely popular spiritual leader Gurmeet Ram Rahim Singh to two consecutive 10-year terms in prison for the rape of two women followers.

The sentence was pronounced amid intense security at a prison in the northern town of Rohtak, where the guru, who calls himself Dr. Saint Gurmeet Singh Ram Rahim Insan, has been in a prison since his conviction on Friday.

Tens of thousands of his supporters set fire to cars and clashed with security forces, that left 38 dead, in the northern state of Haryana just minutes after Singh was found guilty of raping two of his followers.

Prime Minister Narendra Modi condemned the violence but his ruling Bharatiya Janata Party, which is also in power in Haryana, was criticised for failing to anticipate the riots.

More than 100 of Singh's senior loyalists have been placed in detention as a precautionary measure, said Rohtak police chief Navdeep Singh Virk.

He said his officers would use “whatever force is required” to resist the guru's devotees should they again resort to violence.

“If the situation so arises that (we) need to use firearms, my officers have complete authority,” the police chief told broadcaster NDTV.

A judge was flown by helicopter to sentence the 50-year-old spiritual leader known as the “guru in bling” for his penchant for bejewelled costumes.

The rape case was brought against him after an anonymous letter was sent to then-prime minister Atal Bihari Vajpayee in 2002 accusing Singh of repeatedly raping the sender and several other women in the sect.

A judge asked the Central Bureau of Investigation to look into the accusations, but it took years to trace the alleged victims and it was not until 2007 that two women came forward and filed charges.

An estimated 200,000 members of Singh's Dera Sacha Sauda movement had gathered in the city of Panchkula in a show of support a day before his guilty verdict.

Violent protests followed across his power base in Haryana which borders New Delhi, with police deploying tear gas and water cannon.

Modi said on Sunday it was “natural to be worried” as the violence even briefly reached the capital New Delhi.

“Violence is not acceptable in the nation, in any form,” Modi said in his monthly radio address.

“Those who take law in their hands or take to violence will not be spared, whoever they are.” Followers of the self-styled “godman” continue to insist upon his innocence.

India has been rocked by numerous scandals involving popular ascetics claiming to possess mystical powers.

Singh's Dera Sacha Sauda sect describes itself as a social welfare and spiritual organisation but he is no stranger to controversy.

In 2015 he was accused of encouraging 400 followers to undergo castration at his ashram so they could get closer to god.

He also stood trial for conspiracy over the murder of a journalist in 2002.