The Congress on Friday announced that it had appointed Somendra Nath Mitra as its new West Bengal unit chief, replacing Adhir Ranjan Chowdhury. Chowdhury, who was reported to be against an alliance with CM Mamata Banerjee's Trinamool Congress, has been chosen to head the party's campaign committee. Pradip Bhattacharya has been made the chairman of its coordination committee.