Speaking to media after welcoming 62 Sarpanches from Fazilka in the Congress party, Singh said, "We don't approve of any violence and we strongly condemn it."
"If anybody wants to pursue his demands it must be in a peaceful and democratic manner," he said.
The Amritsar MP also clarified that "their reservation demand was within the OBC category for economically weaker sections among the Jats and excluding the creamy layer".
Citing Punjab's case, Singh alleged that Chief Minister Parkash Singh Badal is "deliberately sitting" over the matter.
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The PCC president also favoured reservation for economically weaker sections (EWS) among general categories without disturbing the existing reservation policy.
He said, during his interaction with students in different parts of the state, there were dozens of queries as to why EWS students of general category cannot be provided with some concessions like those from the reserved categories.
He said his party is working on it and it will be incorporated in the party's manifesto.
There will another dharna on June 13 at Jalandhar against "deteriorating" law and order situation in the state, he said.
Amarinder said in the run up to the 2017 Assembly polls, he plans to hold 80 public meetings across the state.
Referring to the "multicrore recruitment scam", in which selective leaks of question papers of recruitment for gazetted and non-gazetted officers allegedly took place by an organised gang, he alleged it involved "a person close to" ruling Badals.
He also said the police have failed to act in the case of attack on Sant Ranjit Singh Dhadarianwale.
"For the same reason I have supported Sant Dhandrianwale's demand for CBI probe as Punjab police had failed to take any action," he said.