Schools and colleges were closed, markets were shut and vehicles remained largely off roads in parts of Nagaland in India today amid a six-hour flash general strike called by the Naga Students' Federation (NSF), protesting against the amended Citizenship Act, officials said.

In Guwahati, neighbouring Assam's biggest city, the curfew, imposed in amid protests against the new citizenship law, was relaxed for seven hours today from 9:00am to 4:00pm local time, our New Delhi correspondent reports quoting police said.

No untoward incident has been reported so far from Nagaland where the shutdown began at 6:00am, they said.

Meanwhile, opposition Rashtriya Janata Dal has called a general strike across Bihar on December 21 in protest against the amended citizenship law.

The shutdown, announced by the NSF on Friday to express resentment of the Naga population against the law, will continue till 12:00pm.

Students appearing for examination, medical staff on duty, media personnel, and those having weddings have been exempted from the purview of the strike.

Nagaland state capital Kohima wore a deserted look with most commercial establishments closed due to the shutdown.

NSF vice president Dievi Yano condemned the amended citizenship law saying it did not take into account the sentiments of the indigenous people of the Northeast.

"The NSF totally resents the injustice done by the central government and we will never support the amended citizenship at, which is the latest weapon of the Centre to divide the Northeastern people," he said.

"The NSF does not believe in classification of illegal immigrants on religious lines as the NSF regards all illegal immigrants must be treated accordingly," he said.

The NSF condemned the three Naga lawmakers Tokheho Yepthomi (Lok Sabha) and K G Kenye (Rajya Sabha) from Nagaland and Lorho S Pfoze (Lok Sabha) from Manipur  for voting in favour of the Citizenship (Amendment) Bill.

The NSF said that along with the apex students outfit North East Students Organization (NESO) it would take all necessary measures to ensure that the law does not take effect in the region.

On Friday, Dimapur Naga Students' Union along with the Joint Committee on Prevention of Illegal Immigrants organized a candlelight vigil in Dimapur which saw hundreds of people taking part in it.

In Guwahati, post-curfew relaxation, long queues were seen outside shops at several places, including Dispur, Uzan Bazar, Chandmari, Silpukhuri and Zoo Road.

Auto-rickshaws and cycle-rickshaws were plying across the city. However, buses were off the roads. Petrol pumps in the city have also opened with vehicles waiting in lines to refuel.

After the Citizenship (Amendment) Bill was cleared by Parliament on Wednesday, violent protests had erupted in Guwahati and other parts of Assam with agitators fighting pitched street battles with the police, forcing the administration to impose curfew and deploying the army.

Meanwhile, The government has extended the suspension of internet services in 10 districts of Assam till December 16 to prevent misuse of social media and maintain law and order situation in the state, said Assam's Additional Chief Secretary (Home and Political Department) Sanjay Krishna.

Internet services were stopped on Wednesday initially for 24 hours in 10 districts of the state and then extended for another 48 hours across the state, which expired this afternoon.