Mr Rai, an MP from Bihar, was addressing a function in the presence of Deputy Chief Minister Sushil Modi on Monday when he made the comments.
Each citizen of the country, he said, should be proud that a "garib ka beta" (the son of a poor family) rose from humble beginnings to become Prime Minister.
"Unki ore uthne waali ungli ko, uthne waale haath ko...hum sub milke...ya to tod dein, zaroorat pari to kaat dein (Any finger or hand raised towards him, (PM Modi) we should together, either break it or if needed, chop it off)," he thundered, wagging his finger.
The comment comes close to a huge controversy over a BJP leader in Haryana, Surajpal Amu, announcing a bounty of Rs 10 crore for the heads of actor Deepika Padukone and director Sanjay Leela Bhansali in the middle of Rajput protests against their film Padmavati.
The BJP has demanded an explanation from Mr Amu, who says he gave the statement as a "Rajput" and not as someone who holds a post in the ruling party.
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