Militants in southern Nigeria say they had no role in the bomb that killed at least four people in the capital, Abuja, on New Year's eve.
The Movement for the Emancipation of the Niger Delta, or MEND, denied any involvement in the attack, in a statement e-mailed to reporters late Saturday.
MEND had claimed responsibility for another bombing in Abuja October 1 that killed 12 people.
Friday's bombing in the capital went off at a busy market where people were celebrating the new year. No one has claimed responsibility for the blast, which wounded another 26 people.
President Goodluck Jonathan has said authorities will track down those responsible for the attack.
On Saturday, he said the bombing appears similar to ones that struck the central city of Jos on Christmas eve.
The radical Islamic group Boko Haram claimed responsibility for the Jos bombings and attacks on churches in the city of Maiduguri the same evening.