Lalu Prasad's Rashtriya Janata Dal has given call for a Bihar bandh on December 21 in protest against the amended Citizenship Act, alleging that it has blown the Constitution to smithereens.

Tejashwi Yadav, Prasad's younger son and heir apparent, made the announcement late on Friday night, urging all political and non-political outfits having 'faith in the Constitution and the principle of justice' to take part in the bandh which was initially scheduled for December 22, but was later preponed so that the police recruitment exams next Sunday were not affected.

'The Citizenship (Amendment) Bill is a black legislation that has blown the Constitution to smithereens. As a mark of protest, Rashtriya Janata Dal will organize a Bihar bandh on Sunday, December 22.

'We appeal to all secular parties, non-political outfits and common citizens who have faith in the Constitution and the principle of justice to wholeheartedly support the bandh and help us make it a success,' he tweeted.

The 30-year-old leader of opposition followed it up with another tweet.

'Correction: Bihar bandh will now be on Saturday, December 21 because police recruitment tests are scheduled on December 22. The rescheduling is being done so that young aspirants are not inconvenienced on account of the bandh.'

Founded in 1997 after which it ruled Bihar for eight more years, the RJD is known for using strong arm tactics to enforce shutdowns which bring normal life to a standstill, sometimes even resulting in violence and massive disruptions of rail and road traffic.

The party has been going through a rough patch since the Lok Sabha polls this year wherein it put up its worst-ever performance and failed to win a single seat.

Turmoil in Chief Minister Nitish Kumar's JD(U) over supporting the Bill in Parliament, which is expected to dent his popularity among the state's Muslims, has prompted the opposition party to come out of torpor and bring itself back into the reckoning with assembly polls less than a year away.

Meanwhile, the BJP - the party in power at the Centre and the JD(U)'s coalition partner in Bihar - took exception to the vociferous opposition to the Bill and condemned it as 'scaremongering and appeasement of Muslims'.

Bihar BJP spokesman Nikhil Anand said in his reply to Yadav's tweet: 'brother, please take the trouble to read the Citizenship Amendment Bill at least once, in its entirety, ask questions that may thus arise and thereafter even run a campaign for further amendments if such a need is felt. But such rants against a legislation that has already been passed by both Houses of Parliament are shameful and nothing more than scaremongering and appeasement of Muslims'.

The legislation has put the entire Northeast on the boil, where people fear that it may exacerbate the problem of illegal immigration, while Muslims across the country apprehend that the move could be a precursor to the country- wide implementation of the National Register for Citizens (NRC).