Thousands of opposition supporters marched through Delhi to India's Supreme Court to demand the election chief resign over alleged electoral roll fraud.

Monday's "March for Democracy" was the latest in a series of demonstrations, with thousands of security forces deployed and roads barricaded in the capital. Thousands of protesters were detained over the weekend.

Congress leader Rahul Gandhi submitted a petition to the court challenging the process, in which tens of millions of names have been struck off the voter rolls.

Opposition parties allege the revision benefits Prime Minister Narendra Modi's ruling Bharatiya Janata Party (BJP). The Election Commission and the BJP reject the charge.

For weeks requests to protest had been denied by police, citing law and order reasons. Attempts to hold a protest by the Cockroach Janta Party (CJP) pressure group over the weekend led to thousands of demonstrators being detained in Delhi.

Gandhi called "all opposition parties, civil society groups [and] all those who believe in democracy" to join Monday's march.

In a press conference, he shared a letter that he and Congress President Mallikarjun Kharge had written to Chief Justice Surya Kant, laying out their concerns with Chief Election Commissioner Gyanesh Kumar's alleged conduct.

After they filed their petition later in the day, Kant responded by saying the matter was already before the court and therefore sub judice - meaning he could not speak about it.

But he added: "You have my assurance that any such petition shall be heard at the earliest possible opportunity, in accordance with the law." There was a heavy security deployment in central Delhi and along the route of the march, with restrictions on traffic and on entry and exit at some metro stations.

A bus carrying Gandhi and other opposition leaders made its way to the court from Barakamba road. Supporters waved flags and chanted his name as the Congress MP and others waved through the windows. Seated a few rows behind him was Neha Bora, a student leader who has gained prominence in the protests.

A few kilometres on, in a place called Mandi House, the bus stopped and Rahul Gandhi and a few others climbed on top of the vehicle to wave at supporters lining up the street in the thousands. Many protesters climbed on to other buses parked here, while some waved flags and chanted anti-government slogans to the sound of drums and lots of cheering.

"If they take away our right to vote, what is left with us?" one protester asked an AFP news agency reporter.

Another protester called the march "a fight to save the very fabric" of India, the world's largest democracy.

Over the past week, top opposition leaders, including Gandhi, have been briefly detained several times while leading protests in central Delhi. On Sunday, the CJP - which is not aed political party - said it would continue protesting until Kumar stepped down.

The CJP, which successfully led a protest over the summer that culminated in India's federal education minister's resignation, had called for a march on Saturday to Jantar Mantar - the best-known protest site in Delhi where the last set of sit-in demonstrations had also happened.

But authorities in Delhi imposed overarching restrictions that made it almost impossible for protesters to travel and reach Jantar Mantar - trains were cancelled, dozens of metro stations were shut and tens of thousands of police and paramilitary personnel were on the roads to detain protesters.

The Home Ministry has now announced demonstrations will no longer be permitted at Jantar Mantar. Three other sites have been listed as alternatives should permission be granted.

The CJP leaders - founder Abhijeet Dipke and co-convenors Saurav Das and Ashutosh Ranka - were dramatically detained from a plane as they landed in Delhi to join the weekend protest.

They were only released a day later - while Dipke returned home to attend his grandmother's funeral, Das and Ranka held a press conference where they said the protests would continue. Both leaders have said they will seek a new protest date from the police.

Over the weekend, the police detained and released thousands of people, including several journalists. Some videos and photos from the protest show police dragging people, including women, by force and pushing them into buses.

The BBC also captured footage of a policeman slapping a detained protester inside a bus. The Delhi police did not respond to questions about the use of violence against protesters.

In a statement, Reporters Without Borders condemned the detention of at least 16 Indian journalists.

"Covering events of public interest is not a crime. It is their job. The police's actions against the press are unacceptable," it said.

Rahul Gandhi said that young Indians who had come to peacefully protest with "love in their hearts, not hatred or anger" had been beaten up.

BJP President Nitin Nabin accused opposition parties and the CJP of trying to destabilise India "at the behest of foreign forces" without elaborating on who the forces were.