Sri Lanka's main Tamil party won a landslide victory Sunday in landmark elections in the battle-scarred north, raising hopes of self-rule for the ethnic minority after decades of war.

The opposition Tamil National Alliance (TNA) won 30 out of 38 seats in the first elections for a provincial council in the former war zone.

Saturday's vote was held amid international pressure for the majority Sinhalese to share power with Tamils four years after the end of the bloody separatist conflict.

The US, which leads international calls on Sri Lanka to improve its human rights record, said the landmark ballot was a "starting point" in reconciliation.

"These elections provided a starting point for that process," the US embassy said in a statement issued in Colombo.

TNA leader C. V. Wigneswaran said the results were an overwhelming vote for self-rule for Tamils.

He repeated his demand for the military to withdraw from the Tamil-dominated north, saying there was no reason for its presence since the end of the war in 2009.

"That (army presence) is the primary problem the Tamils of the northern province are having today," Wigneswaran told foreign media in the region's capital Jaffna shortly after results were announced.

"You have to get rid of the army. They must be put in barracks somewhere else," said Wigneswaran, who is set to become the region's chief minister.

Saturday's vote in the former rebel stronghold has been promoted by the UN Human Rights Council as a step towards ethnic reconciliation following a decades-long war that claimed over 100,000 lives.

Tamils are a minority nationally but a majority in the northern province. Access to the Jaffna peninsula is still controlled by the military, although some of the more stringent security checks have been relaxed. Civilians say they are still under surveillance.

The TNA swept all five districts in the election for the semi-autonomous Northern Provincial Council, results from the Department of Elections showed.

The poll for the council was held amid claims the military tried to intimidate and harass voters and a Tamil candidate.

President Mahinda Rajapakse's United People's Freedom Alliance won just seven seats in a humiliating defeat. His party has won almost every major election since he led the campaign that crushed Tamil Tigers in 2009.

A Muslim party won one seat on the council.

In the district of Jaffna, 400 kilometres (250 miles) north of Colombo and home to over a million Tamils, the TNA secured more than 84 percent of the vote, exceeding its projections of 66 percent.

There were no public signs of celebrations on Sunday in Jaffna where the military maintains a large presence.

Wigneswaran said he was open to talks with the president on power-sharing arrangements in the north, and was seeking devolution in a united Sri Lanka, as set out in a statute in 1987, rather than separation.

"There is a fear of separation, but all we are asking for is a federal state which exists within the boundaries of Sri Lanka," Wigneswaran said. "We are for an undivided Sri Lanka and self-rule under a federal system."

President Rajapakse's brother, Basil, who is also the minister for Economic Development, told reporters in Colombo that the government was ready to cooperate with the newly elected council.

"We are ready to cooperate with them," minister Basil Rajapakse said. "They must now work for the people without misleading the youth and directing them to violence."

Provincial councils were established in 1987 as part of a plan to ease ethnic unrest. But elections had never been held for the northern council, which until now had been under direct presidential control.

Rajapakse has accused the TNA -- a coalition of several Tamil groups, including ex-militants -- of raising expectations of a separate state, a move opposed by the Sinhalese majority.

The government has said it will not give provincial councils power over land and police as originally envisaged in the 1987 statute.

Rajapakse's government has faced international calls to probe what the UN calls "credible allegations" that up to 40,000 civilians were killed in the final months of the fighting, a charge he has denied.

The election comes ahead of a Commonwealth heads of government summit Colombo is hosting in November amid calls by Canada to boycott the meet over human rights concerns.

Western diplomats who were in Jaffna monitoring the vote said the TNA had done better than they had expected.

"This is a clear message on what the Tamils want," one diplomat said, asking not to be named. "It will be difficult to ignore it."