Kolkata, April 8 -- The All India Trinamool Congress (AITC) on Wednesday wrote to the Election Commission of India (ECI), expressing "grave concern" over claims that politically biased officials and observers are threatening electoral neutrality in the state ahead of the Assembly election.

Polling for the 294-member Assembly in West Bengal will take place in two phases on April 23 and April 29, while counting of votes is scheduled for May 4.

Earlier in the day, a meeting between a delegation of the Trinamool Congress (TMC) and the Election Commission of India (ECI) turned tense, with TMC MP Derek O'Brien alleging that the Chief Election Commissioner asked them to leave within five minutes.

He also challenged the Commission to release v...