The CPI(M) on Monday termed the Center’s decision to send a team to West Bengal as unfortunate and regrettable, saying it is an assault on the federal structure mandated by the Constitution. In a statement, the party Politburo said the politically motivated demand by the Trinamool Congress is against the spirit of Constitution and amounts to gross interference in the affairs of the state government. The party said, it further contravenes several judgments of the Supreme Court on this question.