Stung by Governor R S Gavai's nod to CBI to prosecute CPI(M) state Secretary Pinarayi Vijayan in the SNC Lavalin graft case, the party on Sunday decided to observe a 'black day' on Monday.
CPI(M) in a release asked party cadres to hold protest demonstrations and public meetings across the state as part of the 'black day' protest.
Meanwhile, activists of DYFI took out a protest march in several parts of the state and raised slogans against Gavai.
In the state capital, DYFI activists marched towards Raj Bhavan and burned Governor's effigy. The march was stopped by police at Kawadiar junction.
Leaders, who spoke on the occasion, condemned Governor's decision and said he was acting under the "influence" of Congress leaders.
Meanwhile, Youth Congress workers took out a march in some parts of the state welcoming Governor's decision.