New Delhi (CNN) Protesters in India have vowed more civil action against a new citizenship law , even as the Indian government extends sweeping controls on protests and imposes internet shutdowns following deadly country-wide demonstrations.

Tens of thousands of people took to the streets in at least 15 cities across the country, including New Delhi, Mumbai, Bengaluru, and Kolkata on Thursday in a show of nationwide public anger against the law considered by many to be unconstitutional and discriminatory against Muslims.

At least two people died in the protests, which saw violent pitched battles between police and protesters in several cities, including Ahmedabad, Mangaluru, and Lucknow. Police fired tear gas, water cannons and used batons against protesters who pelted stones, vandalized and set fire to buildings and buses. Thousands of people were arrested.

Following Thursday's violence, police in the country's largest and most populous state Uttar Pradesh, where one person died in violent protests, have enforced a law banning public gatherings of four or more people for the next 15 days.

The colonial-era restrictions -- known as Section 144 -- will be imposed across the entire state, Avnish Awasthi, senior official in the Uttar Pradesh Home Department told CNN.

Internet services in the state capital Lucknow will also remain suspended until Saturday evening, after protesters set fire to buildings and clashed with police on Thursday.

"Yesterday, internet connectivity in 73 districts was shut down," Awasthi said. "For the rest of the districts in the states, district officials are making individual decisions."

In the capital New Delhi, section 144 remained in place in three key protest areas Friday, police said.

On Thursday at least one telecoms provider said it was directed to suspend services in six areas of the capital during the protests. It was the first time mobile and internet services had been cut in the capital.

Photos: Protesters rally against India's citizenship bill An Indian Muslim participates in a protest against a new citizenship law that opponents say threatens India's secular identity, in Mumbai, India, on Friday, January 24. Hide Caption 1 of 33 Photos: Protesters rally against India's citizenship bill A Muslim youth waves the Indian flag during a protest held by the Muslim community in Bangalore on January 24. Hide Caption 2 of 33 Photos: Protesters rally against India's citizenship bill A heart made of paper boats with slogans on them rests near a protest in the Shaheen Bagh neighborhood in New Delhi on Wednesday, January 16. Hide Caption 3 of 33 Photos: Protesters rally against India's citizenship bill Protesters light candles near posters of Mahatma Gandhi and politician and social reformer Bhimrao Ramji Ambedkar during a demonstration against India's new citizenship law at Mansoor Ali Park in Allahabad on Tuesday, January 14. Hide Caption 4 of 33 Photos: Protesters rally against India's citizenship bill Police personnel try to protect a man attending a protest against graffiti on the shutters and walls of Church Street condemning Indian Prime Minister Narendra Modi and India's new citizenship law in Bangalore on Tuesday, January 14. Hide Caption 5 of 33 Photos: Protesters rally against India's citizenship bill Activists of All Assam Students' Union and other indigenous organizations participate in a torch procession against the Citizenship Amendment Act in Guwahati, India, on Saturday, January 11. Hide Caption 6 of 33 Photos: Protesters rally against India's citizenship bill Protestors shout slogans outside the Delhi Police Headquarters following clashes between student groups at Jawaharlal Nehru University in New Delhi on Sunday, January 5. The violence injured around 34 people, according to police. Hide Caption 7 of 33 Photos: Protesters rally against India's citizenship bill Placards lie next to Indian Muslims offering prayers during a protest on Saturday, January 4. Hide Caption 8 of 33 Photos: Protesters rally against India's citizenship bill Policewomen detain a student protesting outside Uttar Pradesh Bhawan in New Delhi on Friday, December 27. Hide Caption 9 of 33 Photos: Protesters rally against India's citizenship bill Demonstrators gather at the Quddus Saheb Eidgah grounds to take part in a rally against India's new citizenship law in Bangalore on Monday, December 23. Hide Caption 10 of 33 Photos: Protesters rally against India's citizenship bill Demonstrators sit next to bonfires during dusk as they block a road during a protest in New Delhi on Sunday, December 22. Hide Caption 11 of 33 Photos: Protesters rally against India's citizenship bill Protesters gather by the Jama Masjid mosque in New Delhi to demonstrate against India's new citizenship law on Friday, December 20. Hide Caption 12 of 33 Photos: Protesters rally against India's citizenship bill Policemen with batons charge a protester in Ahmedabad on Thursday, December 19. Hide Caption 13 of 33 Photos: Protesters rally against India's citizenship bill Indians gather during a protest rally in Mumbai on December 19. Hide Caption 14 of 33 Photos: Protesters rally against India's citizenship bill An officer flees a police station damaged by protesters during a demonstration in Lucknow on December 19. Hide Caption 15 of 33 Photos: Protesters rally against India's citizenship bill Chief minister of West Bengal state and leader of the Trinamool Congress Mamata Banerjee, along with party supporters, walks in a mass rally across Howrah bridge in Kolkata on December 18. Hide Caption 16 of 33 Photos: Protesters rally against India's citizenship bill Students from Jamia Millia Islamia, a university in New Delhi, shout slogans during a protest on Tuesday, December 17. Hide Caption 17 of 33 Photos: Protesters rally against India's citizenship bill People standing on roofs in New Delhi watch police gathered next to a demonstration on December 17. Hide Caption 18 of 33 Photos: Protesters rally against India's citizenship bill Students and activists protest outside the Allahabad University campus in Allahabad, India, on Monday, December 16. Hide Caption 19 of 33 Photos: Protesters rally against India's citizenship bill People participate in a mass rally in Kolkata, India, on December 16. Hide Caption 20 of 33 Photos: Protesters rally against India's citizenship bill Demonstrators hold signs at the University of Mumbai. Hide Caption 21 of 33 Photos: Protesters rally against India's citizenship bill A bus is seen on fire following a demonstration in New Delhi on Sunday, December 15. Hide Caption 22 of 33 Photos: Protesters rally against India's citizenship bill A child prays during a condolence event in Guwahati, India, for demonstrators killed in anti-CAB protests. Hide Caption 23 of 33 Photos: Protesters rally against India's citizenship bill Demonstrators shout slogans during a protest in Guwahati on Friday, December 13. Hide Caption 24 of 33 Photos: Protesters rally against India's citizenship bill Relatives of Sam Stafford, 18, who was killed during clashes with police the previous day, react in Guwahati on December 13. Hide Caption 25 of 33 Photos: Protesters rally against India's citizenship bill Indian Muslims demonstrate against the bill in New Delhi on December 13. Hide Caption 26 of 33 Photos: Protesters rally against India's citizenship bill Police fire tear gas during a protest in Guwahati on Thursday, December 12. Hide Caption 27 of 33 Photos: Protesters rally against India's citizenship bill Indian soldiers patrol near a burnt vehicle during a curfew in Guwahati on December 12. Hide Caption 28 of 33 Photos: Protesters rally against India's citizenship bill An Indian police officer aims his gun before firing toward protesters who threw stones in Guwahati on December 12. Hide Caption 29 of 33 Photos: Protesters rally against India's citizenship bill Indian youth congress members hold torches as they demonstrate in New Delhi on Wednesday, December 11. Hide Caption 30 of 33 Photos: Protesters rally against India's citizenship bill Security personnel use batons to disperse students protesting against CAB in Guwahati on December 11. Hide Caption 31 of 33 Photos: Protesters rally against India's citizenship bill Protesters on motorbikes hold placards during a protest against the bill in Guwahati on Tuesday, December 10. Hide Caption 32 of 33 Photos: Protesters rally against India's citizenship bill Demonstrators shout slogans during a shutdown called by the North East Students' Organization in Agartala, India, on December 10. It was hours after lawmakers approved the government's new citizenship bill. Hide Caption 33 of 33

Violence, deaths and arrests

On Thursday, two people died from injuries sustained during a protest in the city of Mangalore, in the southern state of Karnataka, a senior doctor at the Highland Hospital told CNN.

One more person died from firearm injuries in Lucknow city, the capital of northern Uttar Pradesh state, according to a senior doctor at the King George Medical University in the city.

Additional Director General of Uttar Pradesh police, P.V. Ramasastry, told CNN that the death in Lucknow was not directly related to the protests.

Some 3,600 people were arrested as a preventative measure in Uttar Pradesh, police said. In Lucknow, 112 preventive arrests were made while 50 people were booked and arrested under various charges.

In the capital New Delhi, 1,200 people were detained for violating a ban on public gatherings. Police told CNN on Friday those people have been released without charge.

Despite the bans, further protests are planned on Friday at the capital's Jamia Milia Islamia University -- which was the scene of violent clashes between police and protesters on Sunday, and a march from the Jama Masjid -- one of the largest mosques in India -- to the iconic India Gate, in central Delhi.

At the center of the unrest is the Citizenship Amendment Act (CAA), which was passed into law last week. The law that promises to fast-track citizenship for non-Muslim religious minorities, including Hindus, Sikhs, Buddhists, Jains, Parsis and Christians, from Pakistan, Bangladesh and Afghanistan who arrived before 2015.

The government, ruled by Prime Minister Narendra Modi's Hindu nationalist Bharatiya Janata Party (BJP), said the law will provide safe haven for religious minorities who fled persecution in their home countries. Critics say it undermines the country's secular constitution as it bases citizenship on a person's religion and would further marginalize India's 200-million strong Muslim community.

The Indian government had sought to quell any unrest over the law's passing by banning protests and shutting down the internet and mobile services in several parts of the country.

Many of who marched told CNN the government was using the bans on public gatherings to muzzle the voices of Indian people in the world's largest democracy.

"I have my freedom to protest. It is my fundamental right," said New Delhi student Sidharth Singh, 23. "This is not democracy. Why does the government think it is higher than the constitution?"

Thursday's deaths brings the total to at least seven, after five people were confirmed to have died in ongoing protests in the northeastern state of Assam.

Protests in the northeast are different from the rest of the country, however. Many indigenous groups there fear that giving citizenship to large numbers of immigrants would change the unique ethnic make-up of the region and their way of life, regardless of religion.