Social activists Swami Agnivesh and Medha Patkar and Swaraj India chief Yogendra Yadav were among 40 persons detained on Sunday while on way to meet the kin of farmers killed in Madhya Pradesh's Mandsaur district.
They were detained at Dhodhar while on way from Ratlam to Mandsaur where at least five farmers were killed on June 6 in police firing amid violence. They were released on bail later.
Ratlam Superintendent of Police Amit Singh said Section 144 of the Code of Criminal Procedure was enforced in Mandsaur district in anticipation of fear of breach of peace, which prohibited congregation of four or more persons at one place.
He said those detained included five women, including Patkar.
Earlier, these social activists and various farmer leaders paid homage to killed farmers.
Communist Party of India-Marxist state unit chief Badal Saroj dubbed police action against farmers protesting in support of their demands for loan waiver and remunerative prices for farm produce as "undemocratic".