Chennai, Nov 8 (IANS): DMK president M. Karunanidhi Friday asked Prime Minister Manmohan Singh to act according to his conscience and urged India to boycott the Commonwealth summit in Sri Lanka.

Karunanidhi told reporters: "The prime minister has conscience. He should act according to his conscience."

He said nobody from India -- the prime minister or anybody else -- should participate in the Commonwealth meeting to be held in Colombo.

All the major political parties in Tamil Nadu including the ruling AIADMK, DMK, Congress, DMDK and PMK want India to boycott the CHOGM at Sri Lanka in protest against "war crimes" there.

The Tamil Nadu assembly has passed an unanimous resolution urging the Indian government to keep away from CHOGM.

Critics say that Sri Lankan security forces killed thousands of innocent Tamils during the final stages of the war against the LTTE and Colombo has since then refused to give political autonomy to the Tamils.

Karunanidhi said his demand had nothing to do with whether or not the DMK was with the Congress-led UPA government.

"The issue is not about outside support (to the government). We have already come out of the government."