Senior Congress leader Mallikarjun Kharge has resigned as the Leader of Opposition in Rajya Sabha, sources said on Saturday, a day after he filed his nomination papers for the AICC president`s election.

Kharge`s resignation, which the 80-year-old leader sent to Congress president Sonia Gandhi, is in line with the party`s declared `One person, One post` principle that was announced at the Udaipur `Chintan Shivir` in May.