Kejriwal's backing for Yadav comes despite a bitter public falling out with him four months ago leading to the latter's ouster from the Aam Aadmi Party.
"We condemn the way police behaved with Yogendra Yadav and his supporters. This is not right as in this country peaceful demonstration is a fundamental right under Article 19 of the constitution and we condemn such barbaric action against peaceful protestors by police.
A large number of AAP leaders and supporters also expressed their solidarity with their former colleague Yadav.
"India is a democracy. Citizens have a right to protest peacefully. Police have no business to ill treat Yogendra Yadav/supporters. Condemn it. (sic)" AAP leader Ashutosh wrote on Twitter today.
However, AAP leader Sanjay Singh along with other party supporters, who tried to meet Yadav at the Parliament Street Police Station to extend their support to Yadav, was heckled and shouted at by the supporters of the rebel leader.
Swaraj Abhiyan, formed by two expelled AAP leaders, had undertaken Jai Kisan Andolan, a farmers' agitation against the alleged "anti-peasants" policies of the Centre.
The protesters alleged that the policemen manhandled Yadav and other volunteers during the crackdown in the wee hours, a charge denied by the police, which said it was a preventive arrest as they were planning to take out a rally without permission in the high-security area.