Countrywide massive protests against the controversial new citizenship law on Thursday rocked various Indian states, officials said.

Authorities at several states including capital city Delhi imposed restrictions and enforced prohibitory orders to disallow the protests. However, people gathered at the designated venues, where policemen detained them and prevented them from assembling.

A huge contingent of police removed protesters from iconic Red Fort area in the city citing prohibitory orders.

According to police, a prohibitory order has been imposed under section 144 of Criminal Procedure Code, a government order which prohibits an assembly of more than four persons in public places near Red Fort area.

Dozens of people were detained and forcibly removed from the Red Fort area.

Ahead of the proposed march, Delhi police put barricades on its borders and shut down over a dozen metro railway stations in a bid to stop the protest demonstration. The restrictions triggered huge traffic snarls on roads.

"In Jamia Millia University the police cited an excuse that protests were violent and entered inside the campus firing tear smoke shells and bullets. But here we are trying to assemble peacefully why aren't they allowing the peaceful demonstration," said Aarthi, a protester. "Now who is hellbent on forcing people to resort to violent means. This is not democracy."

Aarthi, along with her mother, came to Red Fort to participate in the peaceful protests.

Yogendra Yadav, who had called for the Red Fort protest titled "We the people of India" said despite the prohibitory orders in place, the protest march against the new citizenship law would continue as per schedule.

Yadav was detained by police and whisked away from the spot in a bus.

Reports of protest are pouring in from the southern Indian city of Bengaluru, the capital city of Karnataka.

The police had announced the imposition of prohibitory orders in the city's Town Hall area. However, protesters defied the orders and tried to assemble.

The police arrested a known Indian historian Ramchandra Guha. Television images showed Guha being dragged by the policemen while he was talking to a news channel.

Reports pouring in from Uttar Pradesh said police have imposed prohibitory orders in the entire northern state.

The Uttar Pradesh Police Chief O P Singh asked people not to come out on roads in wake of the prohibitory orders.

However, a rally has been taken out in Lucknow by Samajwadi Party. Defying prohibitory orders, opposition Samajwadi Party legislators and leaders held a protest against the new law.

Protesters gathered outside the Assembly building in the morning ahead of the sitting of the state legislature, despite tight security arrangements and shouted slogans against the contentious legislation.

Protests are underway in the northern city of Chandigarh and at Patna city, the capital of eastern Indian state of Bihar.

In West Bengal, a protest rally is scheduled to be taken out. Chief Minister of the state Mamata Banerjee has in the past three days carried out foot marches in the Kolkata against the citizenship law.

Banerjee, along with chief ministers of Kerala and Punjab, has refused to implement the law in her state.

Over the past few days many organisations, political parties and the civil society have come together to organise protests.

In Odisha's Bhubaneswar, protests would be held round the clock across the city and rallies are scheduled to be held in Mumbai, Chennai, Bhopal Hyderabad and Pune, reports said.

The law aims at granting citizenship to illegal immigrants belonging to six religions - Hinduism, Sikhism, Buddhism, Jainism, Parsi and Christianity - from Bangladesh, Afghanistan and Pakistan. However, it has kept out Muslim immigrants from applying for citizenship.

Opposition parties and civil society members in India criticize the law as contrary to secular principles enshrined in India's constitution as it excludes Muslims.

With this new law, the government would grant Indian citizenship to those non-Muslim immigrants who had entered the country illegally until Dec. 31, 2014. People in the northeastern states fear granting of citizenship to immigrants would endanger their status. Four people were killed in police firing in Assam.

Sixty petitions have been filed in India's top court to challenge the new law.