The Left parties today informed the Election Commission that unless steps are taken to contain the nexus between the Maoists and Trinamool Congress in West Bengal, it will affect the coming Assembly election process in the State. Briefing reporters in New Delhi, CPM leader Sitaram Yechury demanded sealing of state border with the neighbouring states to contain the violence.Earlier in the day, leaders of CPM, CPI, RSP and AIFB have submitted a memorandum to the Election Commission.