In a letter to party's top leaders, copy of which was available with media here, Arora resented that the party lost the last assembly polls due to its own so-called Congressmen.
In an oblique reference to Youth Congress leader Rajinder Singh Raja, who is close confidant of MP Vijay Inder Singla, Arora alleged that such Congressmen were rewarded for stabbing in back of the party.
"This trend, if not put to an end, may prove fatal for the party in forthcoming Parliamentary elections", Arora rued.
The letter was addressed to Congress Vice President Rahul Gandhi, AICC General Secretary Shakeel Ahmed and Punjab Congress president Partap Bajwa.
Arora had lost the last Assembly elections from Sunam seat to Finance Minister Parminder Singh Dhindsa.
When contacted, Arora admitted that he has resigned but refused to divulge reasons.