In an aggressive speech at a rally organised by the party's youth wing, Shah dwelt at length on infiltration from Bangladesh and made a clear distinction between the infiltrators and refugees -- minority Hindus, Christians and Buddhists from Muslim majority Afghanistan, Pakistan and Bangladesh.

While the infiltrators needed to be "identified", it was the "responsibility" of the BJP government at the Centre to ensure refugees can stay back in India, he said.

He gave a call to uproot the Mamata Banerjee-led Trinamool Congress government, and made a veiled reference to her nephew and MP Abhishek Banerjee as he charged the state's ruling party with involvement in a series of corruption cases, besides destroying the law and order situation in the state.

Accusing Gandhi of not taking a clear stand on the recently published draft of the National Register for Citizens (NRC) in Assam for the sake of vote-bank politics, Shah asserted that his party was committed to completing the registration process to identify infiltrators.

"Mamata Di, NRC will not stop just because of your opposition. You are free to oppose. Congress leader Rahul Gandhi is free to oppose. But it is our commitment that we will complete NRC in Assam, by following the due process of law, and identify all infiltrators one by one," Shah said at a rally here.

Banerjee has been strident in her criticism of the NRC after 40 lakh people did not find a place in the document published on July 30.

Asking Gandhi to spell out his stand on NRC, Shah pointed out that the work on the document was being done as per the Assam accord which was signed by then Prime Minister Rajiv Gandhi - Rahul Gandhi's father - in 1985.

"Now for vote-bank politics, Rahul Gandhi is not taking a clear stand," Shah said at the rally organised on Mayo Road in the heart of the city.

Virtually throwing a challenge to Gandhi and Banerjee, Shah said they should clarify their priority -- country's security or votebank politics.

Reminding Banerjee that in 2005 she had thrown papers at then Lok Sabha Speaker Somnath Chatterjee and stalled the House demanding removal of Bangladeshi infiltrators, Shah said she has changed her stance as the infiltrators now vote for her Trinamool.

Unlike other state BJP leaders, Shah did not talk of bringing out an NRC in Bengal, but said the state would not be in fine fettle if infiltration - 'rampant' during Banerjee's rule - was not stopped.

"And the best way to stop infiltration is NRC. So, the NRC process in Assam has to be completed," he said.

Shah also charged Banerjee with spreading "misinformation" in Bengal that along with infiltrators, refugees will also be driven out of India because of the NRC.

"I assure all refugees in Bengal that the BJP government is bringing the Citizenship Amendment Bill, 2016. This Bill has the provision to give citizenship to Christians, Buddhists and Hindu refugees who have come from Afghanistan, Pakistan and Bangladesh. There are no plans to send any refugee back."

Shah asked the two opposition parties to speak out before the general election whether they would back the legislation in Parliament.

Ridiculing the critics of NRC who have expressed concern about human rights of infiltrators, Shah wondered whether the Congress and the Trinamool were "not bothered" about the "human rights of the Hindus and Muslims of West Bengal".

Playing the Hindu card, Shah warned Banerjee not to create hurdles in Durga idol immersion or the Saraswati worship in the state, saying his party activists will "bring down Banerjee's secretariat brick by brick" if such things ever recurred.

The Durga Puja immersion processions were delayed over the past few years in certain parts of Bengal as Muharram rallies coincided with the immersion of idols.

Shah said he would tour all districts in Bengal and start an agitation to throw out the Trinamool Congress.

Describing the BJP as the only party capable of ushering in progress in the state, Shah said : "Since the Trinamool Congress government came to power, there has been a series of corruption (cases) starting from the Narada scandal, Saradha and Rose valley ponzi scams... syndicates and the unlawful activities of cattle mafia and coal mafia."

On the issue of graft, Shah indirectly referred to Abhishek, widely regarded as her prospective successor.

"During the 14th finance commission, the Narendra Modi government allotted Rs. 3,59000 crore to Bengal as compared to Rs. 1.32,000 crore given by the UPA government during the previous finance commission. Where did all the money go? Did it disappear in the pockets of syndicates and the nephew?" Shah questioned.

He also urged the people of Bengal to ensure the BJP won 22-plus Lok Sabha seats in Bengal in 2019.