At least 29 people have been killed during violent protests in India following the conviction of a spiritual leader who raped two women, angering thousands of his supporters.

Followers of Gurmeet Ram Rahim Singh, the head of spiritual group Dera Sacha Sauda, rejected a court verdict that found him guilty of raping two female members of the quasi-religious sect.

His backers rampaged in response, setting a train on fire and attacking government buildings and journalists in towns across the northern states of Punjab and Haryana.

Singh, 50, who has written and starred in his own films, urged his followers in a televised appeal on Thursday not to resort to violence.

But AK Dhir, one of his lawyers, said Singh was innocent and his followers had every right to express their outrage.

Around 200,000 of his supporters descended on Chandigarh, where the trial was carried out, in the run-up to the ruling.

After clashes erupted, more than 15,000 troops and police officers were deployed and a curfew imposed, with police using tear gas and water cannons to control the crowds.

Police arrested 81 people while India's Prime Minister, Narendra Modi, said the "law and order situation is being closely monitored".

"The instances of violence today are deeply distressing," he wrote on Twitter. "I strongly condemn the violence & urge everyone to maintain peace."

Protests also erupted in New Delhi and in the neighbouring state of Rajasthan. Supporters of the self-styled "godman" set fire to buses and two empty train coaches in the capital.

Vehicles set on fire by suspected Dera Sacha Sauda sect members in Panchkula, India (EPA)

Reports said the violence had left more than 200 injured, with some of the victims treated for bullet wounds after police were said to have fired live rounds into the crowd.

Singh's crimes date back to 2002 and took place at the headquarters of his Dera Sacha Sauda group in the northern town of Sirsa.

Dera Sacha Sauda claims to have more than 60 million followers around the world. The sect, founded in 1948, campaigns for vegetarianism and against drug addiction.

It also runs free health services and has taken up social causes including organising weddings for poor couples.

Followers of Singh throw stones at security forces during clashes in Panchkula (Getty)

Such sects have huge followings in India, and it is not unusual for leaders to have small, heavily-armed private militias protecting them.

On his Twitter page, Singh lists varied talents such as a "spiritual saint", philanthropist and "versatile singer", as well as an "allrounder sportsperson", film director and writer.