Imran Masood at a police station in Saharanpur after his arrest.

Imran Masood, the Congress candidate from Saharanpur in West Uttar Pradesh who was filmed declaring that he will kill Narendra Modi , was arrested from his residence around 4 am today.A criminal case was registered against him yesterday after a video of him threatening to "chop Modi to pieces" went viral on the web. Apologising for his comments yesterday, he told NDTV, "I meant that I would teach him a lesson."Hours after his arrest, Congress Vice President Rahul Gandhi's rally was cancelled in Saharanpur. He was to campaign for Mr Masood today.Condemning Mr Masood's remarks, senior party leader Digvijaya Singh had said yesterday that the comments should not go unpunished.An FIR or First Information Report accused Mr Masood, 40, of violating the election code of conduct, but it was not clear when and where the comments were made.The police say they received the video CD on Thursday. Mr Masood claims he spoke those words eight months ago, when he was with the Samajwadi Party.In the CD, Mr Masood says, "I am a man of the street, ready to give my life for my people. I am neither afraid of death or of killing. He thinks this is Gujarat. There are only 4% Muslims in Gujarat. There are 42% Muslims here."Senior BJP leader Arun Jaitley said the comments reflect a mindset that believes "abusing Modi is an expression of aggressive secularism." He also referred to Sonia Gandhi's "Maut Ka Saudagar (merchant of death)" barb in 2007 against Mr Modi. (Read: BJP sowing seeds of poison in its hunger for power, says Sonia Gandhi) Mr Modi, 64, is contesting his first parliamentary election from Varanasi, 800 km away in India's largest and most politically vital state. In his speech, Mr Masood warns the BJP leader against "turning Uttar Pradesh into Gujarat."

Mr Modi's critics accuse him of not doing enough to stop the 2002 riots that tore through his Gujarat. A Supreme Court inquiry has said there is no evidence of Mr Modi's alleged collusion in the violence; a local court upheld that report recently.