With his Rajya Sabha term expiring next month, PM Singh will file his nomination papers on Tuesday seeking re-election in the biennial poll from Assam. Singh has been representing the North Eastern state for the last three terms. PM will undertake a two-day visit to the state from 8th May. Election to the seat would be held on 24th May. Singh, whose present term ends on 14th June was elected for a third term in 2001 and two years later he became Prime Minister.