Sangrur MP Bhagwant Mann resigned as AAP's Punjab chief today, a day after party convener Arvind Kejriwal apologised to a SAD leader for accusing him of being involved in the drug trade.

The Delhi chief minister's apology drew flak from his party's leaders and MLAs in Punjab, who said they were "stunned" by the move and "disappointed" as Kejriwal had not kept them in the "loop".

Mann announced his resignation on Twitter.

"..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" of Punjab (sic)," Mann said in a tweet.

Kejriwal had yesterday apologised for levelling charges of involvement in drugs trade against SAD leader former Punjab minister Bikram Singh Majithia, saying he had learnt that his allegations were unfounded.

The chief minister in his apology letter had said, "In the recent past I made certain statements and allegations against you (Majithia) regarding your alleged involvement in the drug trade. These statements became a political issue."

"Now I've learnt that the allegations are unfounded. Hence there should be no politics on such issues. I hereby withdraw all my statements and allegations made against you and apologise for the same," he said.

Leader of Opposition in Punjab Sukhpal Singh Khaira said that he was "stunned" by the apology by Kejriwal.

"We're appalled n stunned by the apology of @ArvindKejriwal tendered today,we don't hesitate to admit that we haven't been consulted on this meek surrender by a leader of his stature," he said on Twitter.

In another tweet, Khaira said, "We promise to continue our tirade on the burning issue of drugs destroying the youth of Punjab".

"I fail to understand the timing of Kejriwal's apology when STF of PB has stated to the High Court today that there's substantial evidence to proceed against Bikram Majitha on the issue of drugs-khaira (sic)," he had tweeted yesterday.

The AAP's Kharar MLA Kanwar Sandhu also reacted sharply to the apology, tweeting , "Arvind kejriwal' 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."

"Shocked & disappointed 2 know abt the apology tendered by Arvind Kejriwal 2 Majithia. I still believe drugs wud not have taken so much young lives had the previous Govt not patronised drug mafia. Our fight against drugs continues,"

the party's Punjab unit co-president Aman Arora tweeted.

Lok Insaf Party (LIP) leader Simarjeet Singh Bains was also miffed at the apology by Kejriwal to Majithia. The LIP is AAP's ally in Punjab.