A former political proxy for Sri Lanka's defeated Tamil Tiger rebels swept the country's northern provincial election, according to results released on Sunday.
It was being seen as a resounding call for wider regional autonomy in areas ravaged by a quarter of a century of civil war.
The country's elections commission announced the Tamil National Alliance will form the first functioning provincial government in the northern Tamil heartland after securing 30 seats out of 38 in Saturday's voting.
President Mahinda Rajapaksa's coalition won eight seats.
The win provides a platform for the party to campaign for an autonomous state, although the provincial council is a largely toothless body.
The Tamils have fought unsuccessfully for six decades - through a peaceful struggle and then the bloody civil war - for self-rule.
The elections are seen by the United Nations and the world community as a crucial test of reconciliation between the Tamils and the majority ethnic Sinhalese, who control Sri Lanka's government and military.
The result also suggests that a vast majority of voters prefer self-rule over Mr Rajapaksa's effort to win them over through infrastructure development.
However, the provincial council is largely powerless and the new government led by former Supreme Court Justice CV Wigneswaran will have to contend with a centre-appointed governor who will control most of the council's affairs.