MDMK has four members in the Lok Sabha but the group had split as two of its MPs, L Ganesan and N Ramachandran, have parted ways with Vaiko.
The UPA government has become a minority one, MDMK leader Vaiko said in a statement in Chennai after the withdrawal of support by the Left parties.
Stating that India should not implement the nuclear deal at any cost, Vaiko said the party was opposing the deal as it would pledge India's sovereignty to the United States.