"My friend Vijayakanth has taken a decision contrary to the expectations of the people and his party cadres. It is a wrong decision. After the outcome of election results he will realise that it was a wrong decision," state Congress Committee President E V K S Elangovan told reporters.
DMDK had earlier called itself the "real alternative" to both AIADMK and DMK and declared that it would go it alone in the polls.
Congress and DMK had last month forged an alliance to face the Assembly election together in Tamil Nadu.
"I refuse to comment on it," Elangovan said when asked to comment on the Supreme Court commuting to life imprisonment, the capital punishment awarded to three persons in the case relating to burning to death of three college girls in Dharmapuri in Tamil Nadu in 2000 following the conviction of AIADMK supremo Jayalalithaa, who was then in the opposition.
He, however, added that the "curse of the kin of those killed in that incident will trounce AIADMK in this election."