NEW DELHI, March 16 (Xinhua) -- India's anti-corruption party - Aam Aadmi Party (AAP) or common man's party chief in northern state of Punjab resigned Friday amid allegations of defamation.

The resignation of Bhagwant Mann, a lawmaker in Indian parliament, from party post comes after AAP convener Arvind Kejriwal apologized to former Punjab minister Bikram Singh Majithia for alleging that he was involved in the "drug trade."

Kejriwal is the chief minister of New Delhi.

"I'm resigning as a president of AAP Punjab. But my fight against drug mafia and all kind of corruption in Punjab will continue as an 'Aam Aadmi' (common man) of Punjab," Mann tweeted.

Majithia had filed a defamation case against Kejriwal and others following an allegation made by AAP during campaigning in the Punjab local elections.

Kejriwal's apology has not gone well his party members in Punjab, who described the decision taken by him as unilateral.

"Arvind Kejriwal's apology to Bikram Majithia in the defamation case on drugs is a let down to the people, especially the youth of Punjab. We in Punjab have not been taken into the loop. Our fight for Punjab continues," writes a local lawmaker Kanwar Sandhu.

Kejriwal is facing couple of defamation cases.