The former Pakistani prime minister says his party will win the most seats in Pakistan's national assembly, but an outright majority appears unlikely.
Nawaz Sharif declares victory in Pakistan election after early results
The PML-N leader told jublilant supporters at his party headquarters in Lahore that "we should thank Allah that he has given PML-N another chance to serve you and Pakistan"and invited other parties to work with him.
According to the unofficial, partial results it appeared that no single party would win a simple majority of 172 seats in the national assembly, raising the prospect of protracted talks to form a coalition government.
"Whatever promises we made with our youth, I assure you that we fulfil each of them. Results are still coming but there is a confirmation that PML-N will emerge as the largest party," Mr Sharif said. The parties of Mr Sharif and cricketer-turned-politician Imran Khan, head of the Movement for Justice party, were leading their rivals as results began to appear on television screens last night.
The elections were marred by several incidents of violence and widespread allegations of rigging in its largest city, but the threat of widespread attacks on polling booths by the Pakistani Taliban failed to materialise.
Observers had predicted a record turnout, and long lines of people queued throughout the hot day and into the night at polling stations across the country.
The election commission had originally set voting to end at 5pm, but extended by on hour nationwide and up to three hours in some constituences in Karachi where voting started late.
Unlike in Punjab province, where voting was largely unmarred by fraudor violence, the commission declared the elections in Karachi, in Sindh province, to have been tainted by rigging and other irregularities.
It said that polls would be held again in at least 40 polling stations, but it was unclear if the entire vote would be invalidated or what effect this might have on the overall outcome.
"We have been unable to carry out free and fair elections in Karachi," the commission said.
More than 86 million people were eligible to vote in the national elections that will see the first transfer of power from an elected government that has served a full term to another in Pakistan, a country that has been ruled by the military for more than half of its 66-year history.
The main issues for voters are the failing economy, an energy crisis that causes widespread power cuts, endemic corruption, crumbling infrastructure and Islamist terrorism.
Voters have been electrified by an unpredictable race dominated by Mr Sharif and Mr Khan's Movement for Justice party.
While Mr Sharif , 63, has cast himself as the experienced, business-friendly candidate who can steer Pakistan on to a stable course of development, Mr Khan, 60, had tapped into a deep desire for a change in the political class by many urban middle-class Pakistanis and the youth tired of the old political dynasties and the system of patronage politics. Both men have similar, centre-right positions, however, and both favour negotiations with the Pakistani Taliban.
Initial results from the country's 70,000 polling stations trickled in last night.
The contest was likely to hinge on voter turnout, especially among the nearly 40 million voters under the age of 35. This demographic, which has not participated in great numbers in past elections, was thought to favour Mr Khan's message of meritocracy, anti-corruption, and an end to Pakistan's cooperation with the United States in its war on terror.
"We have tried everyone else and all they do is fill their own pockets," said Ishtiaq Mohammed Khan, 20, as he waited to vote at a polling station in the working-class Mehmoodabad neighbourhood of Karachi. "Inshallah, Imran Khan will make a new Pakistan."
The election's result will most likely be decided by the tally in Pakistan's largest and richest province, Punjab, where Mr Khan and Mr Sharif have focused their campaigns.
Election fever gripped Punjab's capital city Lahore last night, as supporters of both the front-runner parties flooded the streets waving cricket bats and holding stuffed tigers, the election symbols of Mr Khan's and Mr Sharif's parties respectively.
"It's better to try a lesser evil instead of trying a novice," said one Lahore voter, Haji Mohammad Younus told the Associated Press. "The lesser evils at least have the experience of governing. They might be corrupt but they have lately realised that they have to deliver if they want to survive."
But opinion polls suggest that no party will emerge with a mandate or even a simple majority in the 342-member national assembly. A likely outcome is a weak coalition government that is unable to enact desperately needed reform or assert its authority in the sphere of security and foreign policy, which has long been dominated by the military.
The Pakistan Peoples Party (PPP)is expected to do poorly in the elections, though opinion polls had the party carrying its home province Sindh and coming in third overall. Most voters are furious with the party's handling of the economy, inflation, the power crisis and militant attacks.
The PPP and its partners in the outgoing government, the secular Awami National Party (ANP) and the Muttahida Qaumi Movement, have been unable to campaign freely because of a campaign of terror by the Pakistani Taliban against more liberal parties.
Taliban leader Hakimullah Mehsud said in a statement on Friday that he had ordered his commanders to dispatch teams of suicide bombers to target voting sites in attacks on the "infidel system" of democracy.
More than 130 people died over the month of campaigning leading up to the elections, and this tally was added to as Pakistanis braved the attacks to vote yesterday.
firstname.lastname@example.org with additional reports from Agence Frane-Presse