Scores of BJP workers on Sunday staged a demonstration outside the CPI(M) office in New Delhi, protesting against the murder of a 38-year-old party worker allegedly by supporters of the Left party during a poll victory rally in Kerala.
Around 150 protestors have been detained, police said.
Several police teams were rushed to the spot in New Delhi area and the entire area was barricaded.
CPI(M) workers had also come out of the building to confront the protesters, a senior police official said.
BJP worker Pramod (38) had sustained head injuries after he was allegedly hit by a brick following a clash during a victory rally by CPI(M) workers at Idavilangu in Kerala on Thursday. He died the next day.
BJP has been targeting the Left over the alleged attacks on its workers in Kerala in the run up to the polls.
BJP chief Amit Shah had on Saturday accused the Left Front of "violating" the people's mandate.
BJP had said it will not sit quiet if the "cycle of violence" continues in the state as it claimed that it has emerged as a powerful alternative voice to the two main fronts led by CPI(M) and Congress.