CPI(M) general secretary Sitaram Yechury said he wrote the letter to register the party's "strong condemnation" over "continued violence, terror and intimidation" unleashed by the ruling Trinamool Congress party in West Bengal.
He said during the course of the third round of polling, held on April 21 four CPI(M) leaders were murdered.
"I am writing to you because all poll related violence comes under the remit of the Election Commission of India as mandated by our Constitution. So far, no action appears to have been taken against the culprits who have perpetuated such murderous assaults.
"I am requesting you (CEC) to please take necessary action immediately and thereby instill confidence among the people to fearlessly exercise their democratic right of franchise," he added.
Two CPI(M) cadres were killed allegedly by Trinamool Congress workers in post poll violence at Lodhna under Khandaghosh assembly constituency in Burdwan district, police said today.
