Voting is under way in Sri Lanka's general election, with the poll viewed as a referendum on the political future of former president Mahinda Rajapaksa.
The alliance that swept him from power is also seeking a stronger mandate for reforms, as the nation on Monday elects the 225-member parliament.
The main contest is between Rajapaksa's Sri Lanka Freedom Party (SLFP) and outgoing prime minister Ranil Wickremesinghe's United National Party (UNP), which formed a minority government after Rajapaksa was ousted in January's presidential election.
Will Rajapaksa make a political comeback in Sri Lanka?
Both are vying for the post as prime minister.
According to the election commissioner, Mahinda Deshapriya, polling stations opened as planned and after several hours of polling, everything had run smoothly.
He said, "no major incidents have been reported, and voting is going on smoothly as planned. There has been a brisk turnout of voters in Colombo."
Rajapaksa was defeated in January by his former health minister, Maithripala Sirisena, amid a swell of opposition by ethnic Tamil and Muslim voters, owing to his majority Sinhala Buddhist platform.
However the new president Sirisena then called for early elections after his reforms were blocked in the parliament by politicians loyal to his rival.
Rajapaksa's decision to run for a seat in parliament against his president's wishes caused a split in the SLFP.
Sirisena is backing Wickremesinghe, with whom he formed an alliance after breaking away from Rajapaksa's government.
Rajapaksa is confident of returning to power after drawing crowds of thousands of people on the election trail, despite the 69-year-old and his closest relatives facing corruption allegations.
|Sri Lankan Prime Minister Ranil Wickremesinghe has promised to build on the gains of the revolution that ended Rajapaksa's rule [Getty Images]
However, the reformist alliance that rallied to elect President Sirisena in January remains intact.
Some observers say it should secure a majority and may call on the backing of smaller parties if needed.
Wickremesinghe has promised to build on the gains of the revolution that ended Rajapaksa's nine-year rule.
Turnout a decider
Al Jazeera's Nidhi Dutt, reporting from Rajapaksa's support base of Kurunegala, said a key question in the vote was how many people would turn up at the ballot box.
"If there is an enthusiastic turnout, like there was in January, that could spell the end of (Rajapaksa's) political career but if in fact there is an element of fatigue and many people stay away from the ballot box, that could give him a boost," our correspondent said.
Sri Lanka's elections pit its past against its future
A total of 196 politicians will be elected from party lists in multi-member districts. The rest will be elected from national lists, with party leaders deciding who gets a ticket.
Election monitors said more than 1,500 complaints had been received and three election-related deaths reported during the campaign.
Long term EU election observer from Cyprus, Despina Efstathiou, who is monitoring the handing over of ballot boxes to the election presiding officers in downtown Colombo, told the Reuters news agency that proceedings were being closely watched.
The voting is underway at 12,314 polling centres across the nation as voters choose from 6,100 candidates.
The polls opened at 7am local time (01:30 GMT) and will close at 4pm. The results are due on Tuesday.
Source: Al Jazeera and agencies