Making a suo moto statement in the Assembly, Jayalalithaa said, "I don't have any power to alter the Presidential order rejecting the mercy petitions of the three," -- Murugan, Perarivalan and Santhan.
She appealed to political parties "not to send signals" that she had powers to overturn the Presidential orders and save the three from the gallows.
The three, sentenced to death in the Rajiv Gandhi assassination case, are scheduled to be hanged on Sept 9.
The President had twice rejected their mercy petitions of the three who were awarded the capital punishment by a Special Court here, which was upheld by the Madras High Court and the Supreme Court.
Charging the DMK president M Karunanidhi with adopting "double standards" and enacting a "fake drama", Jayalalithaa said Karunanidhi, when he was Chief Minister, had recommended to the Governor to reject the mercy petitions of the three and commute the death sentence of Nalini, to life.
A decision in this regard was taken on April 19, 2000 at a cabinet meeting chaired by Karunanidhi, she said.