The founder of India's "cockroach" protest movement, Abhijeet Dipke, has been detained in Delhi ahead of a planned march in the heart of the capital.

His detention follows a police warning against holding Friday's march, with thousands of security personnel deployed across the city to prevent the gathering.

Dipke's youth-led Cockroach Janta Party (CJP) is demanding the resignation of India's election chief over allegations of voter list manipulation. The Election Commission denies the charge.

The group had asked its supporters to come to a park in Connaught Place, one of Delhi's busiest commercial districts, to wave the Indian flag.

The turnout was smaller than at earlier CJP demonstrations though the crowd seemed to be swelling. The BBC saw some young protesters being detained and shoved into a bus which already held some female detainees - there were about 50 female police personnel in the bus, vastly outnumbering the protesters.

Dipke had just left home and was moments away from reaching his vehicle when the BBC saw police officers surround him and force him into a police car. Some CJP supporters tried to block the vehicle from leaving.

Anish Gawande, the opposition politician at whose house Dipke had been staying, questioned why police had detained him. Police have not yet publicly confirmed the grounds for the detention. "Detaining a lone man walking with the national flag in his hand is a bit of a joke," Gawande said.

It was the second time in less than a week that Dipke was detained. Last Saturday, police boarded his plane shortly after it landed in Delhi and took him away before he could reach a planned demonstration.

Police barricades and mass detentions prevented thousands of other protesters from reaching the venue. Dipke was released the following day, but two other CJP leaders - Saurav Das and Ashutosh Ranka - were later jailed for five days after entering Jantar Mantar, a protest site recently declared off-limits by police. Friday's march was partly intended to show solidarity with the two jailed leaders.

Dipke had acknowledged the possibility of being arrested again. In a video message on Thursday, he urged supporters unable to travel to Delhi to raise the Indian flag in their own towns and cities.

"I also may be jailed after this, but I am not worried. Tricolour is my pride and I will raise it," he said.

Earlier on Friday, police had served Dipke with a notice warning him against holding the march without permission.

Authorities also closed Central Park for two days, citing "administrative reasons". Police offered to let a small group wave the national flag and sing the anthem at another location.

The CJP responded by changing its plans, urging supporters to enter Connaught Place in groups of fewer than five, unfurl the flag, take a photograph and leave.

"Waving the Tiranga is not a crime," the group said in a social media poster, using the Hindi name for India's tricolour flag. It encouraged supporters to share their photographs online.

By the time the protest was due to begin, around 200-300 people had gathered near Central Park. Prevented by police from entering, they moved around the park, waving flags and shouting slogans.

Among those detained was Neha Bora, a prominent leader of the left-wing All India Students' Association (AISA) who has emerged as one of the faces of the recent protests. She was also detained during last Saturday's crackdown.

Security personnel, meanwhile, continued to arrive. More officers emerged from buses stationed around Connaught Place, joining the thousands of police and paramilitary personnel already deployed. Journalists also crowded the streets, with police and media in much larger numbers than the protesters.

Barely five months old, the CJP began as an online campaign in May after India's chief justice likened some unemployed young people to cockroaches. Dipke embraced the insult and turned it into a rallying cry.

By July, the group had become a formidable force, drawing thousands of young people into protests over leaked examination papers. A march towards Parliament in July descended into clashes with police, bringing the movement wider attention and intensifying pressure on the government. The unrest eventually forced the resignation of India's education minister, Dharmendra Pradhan.

Police cited earlier demonstrations in their warning against Friday's march. In the notice served to Dipke, they accused the CJP of defying restrictions and said previous attempts to march towards Parliament had led to violence and damage to property.

They also warned that a large gathering in Connaught Place could disrupt traffic, affect businesses and obstruct emergency vehicles.

The CJP wants Chief Election Commissioner Gyanesh Kumar to resign, accusing the poll panel of favouring Modi's ruling Bharatiya Janata Party (BJP). Both the commission and the government deny the allegations.

At issue is a sweeping revision of electoral rolls, known as Special Intensive Revision (SIR), that critics say has removed more than 130 million names, putting legitimate voters at risk of losing their right to vote.

Friday's march comes less than a week after police prevented the movement's last mass demonstration from taking place, detaining its leaders - Das, Dipke and Ranka - and putting the city under a sweeping security lockdown.

Tens of thousands of police and paramilitary personnel had fanned out across Delhi, sealing roads, shutting metro stations and intercepting protesters long before they could reach Jantar Mantar, where the CJP had planned its mass demonstration.

The BBC witnessed dozens of people being detained, including journalists and students. In footage from across Delhi, protesters could be seen shouting as police seized them by the arms, dragged them across the pavement and pushed them into waiting buses.

Those who managed to gather elsewhere were swiftly dispersed. There were also reports of protesters being assaulted by police.

The BBC 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.

The scale of the crackdown drew widespread outrage, with the CJP likening the police action to India's Emergency, when civil liberties were suspended between 1975 and 1977.

Delhi police defended the measures as necessary to maintain public order and prevent unauthorised gatherings. Dipke, Das and Ranka were released on Sunday after agreeing to maintain peace and good behaviour.

Police then took Jantar Mantar off Delhi's list of approved protest sites, designating three alternate venues. Built in the 18th Century to study the stars, the observatory sits near parliament and has long been one of India's most recognisable stages for public dissent. The CJP accused the authorities of pushing protesters away from the seat of power to make their demonstrations less visible and easier to ignore.

On Tuesday, Das and Ranka returned with a handful of supporters, unfurling the Indian flag and shouting slogans against Kumar.

Police said they had entered the restricted site without permission, some by climbing over a locked gate, and breached the conditions of their release.

The following day, the two were sent to jail for five days in judicial custody. Another organiser, Ajinkya Shinde, was released on a bond to maintain peace and good behaviour.

The CJP's campaign is unfolding alongside a separate wave of protests by India's opposition parties, which have also accused the Election Commission of manipulating voter rolls to benefit the BJP.

Last week, opposition leader Rahul Gandhi and other lawmakers attempted to march to the commission's headquarters in Delhi but were stopped by police and detained. Opposition politicians have since taken their grievances to President Droupadi Murmu and marched towards the Supreme Court.

Although the CJP, student organisations and opposition parties have largely protested separately, their demands have increasingly converged. Gandhi has condemned the arrests of CJP organisers and called for Jantar Mantar to be reopened to peaceful demonstrators.

Home minister Amit Shah, meanwhile, has accused opposition parties of spreading falsehoods about the voter-verification exercise and defended the Election Commission's independence.