Last year, three senior Congress legislators in Manipur had quit the party.
As the BJP released its first list of 31 candidates for the upcoming two-phase Manipur assembly elections, scheduled for March 4 and March 8, the ruling Congress suffered a setback after three of its key senior leaders quit the party on Monday.
Incumbent legislators Nemcha Kipgen and Vungzagin Valte tendered their resignation letters to state party chief TN Haokip as well as assembly Speaker Th Lokeshwor. With their resignations, the strength of the Congress in the assembly has reduced to 45.
The vice president of the Congress' Manipur unit S Achouba also resigned from primary membership of the party.
Last year, three senior legislators - N Biren Singh, Y Erabot Singh and Francis Ngajokpa - had quit the Congress and joined the BJP. Sources said that Mr Kipgen, Mr Valte and Mr Achouba might also join the BJP.
The BJP has claimed that several senior ministers would also quit the Congress ahead of the polls.
Mr Kipgen had been elected from the Kangpokpi assembly seat in the last elections whereas Mr Valte was elected from the Thanlon constituency.
The Congress has been ruling in the state of Manipur for the last 15 years.
Manipur is facing a crisis after the United Naga Council called for an economic blockade on November 1 to protest against the state government's decision to bifurcate Naga dominated areas and create seven new districts. The economic blockade has affected the key road links to the state, including National Highway-2 and National Highway-37, which in turn has created an acute shortage of essential goods and supplies.