"The posters are the result of (action from) a rival camp. I firmly believe none of my sons would have been the reason for it. Any one who works with the intention of splitting the party will not succeed in the attempt," he told reporters.
Asked if those responsible had been identified, he said "they may hide behind the drama enacted by them. Not just the party, even those who had tried to destabilise me have not succeeded and will not succeed," he said.
He recalled that DMK had Tuesday issued a statement warning of action against those who had put up such posters.
Chennai was awash by posters of Alagiri for his 62nd birthday celebrations today.
Sibling war came to the fore recently after Karunanidhi made it clear that his younger son M K Stalin would be his successor and Alagiri indicating he would oppose the decision saying DMK was "not a mutt”.