Update: 03:30 GMT - Jaffna
As votes continue to be counted across the island, Sri Lanka's former defence secretary Gotabaya Rajapaksa seems to have taken an early lead against Sajith Premadasa, despite a large turnout in the Tamil North-East.
Results in Tamil districts so far show an overwhelming vote for Sajith Premadasa.
However, in the Sinhala south, Rajapaksa has won over key districts, with many regions still to be declared.
Votes are still being counted with results expected throughout the day.
Update: 03:00 GMT
The Vanni district results have been announced. Premadasa wins over 174,000 votes (82%) to Rajapaksa's 26,000 (12%).
Update: 02:00 GMT
Results from Mannar show Premadasa winning over 53,000 votes to Rajapaksa's 6,400. In Mullaitivu, Premadasa won over 47,000 votes to Rajapaksa's 4,200. Vavuniya is still to be declared, but the Vanni district seems to have voted overwhelmingly in favour of Premadasa.
Premadasa wins over 74,000 votes in the Mutur polling division to Rajapaksa's 4,900 - more than 90% of the votes. The Trincomalee district is still to be declared.
Update: 01:00 GMT
Sajith Premadasa won over 300,000 votes in total in the Jaffna District according to early reports, almost 290,000 votes more than rival Gotabaya Rajapaksa.
District-wide figures currently reported are 312,700 votes for Premadasa and 23,200 for Rajapaksa.
The Jaffna district is made up of the Jaffna and Kilinochchi regions.
Update: Sunday November 17, 00:45 GMT
The two leading candidates are currently within around 5% of each other. Although Gotabaya Rajapaksa took an early lead from the first few late-night results after close of voting, results from Jaffna came fast after dawn giving Sajith Premadasa the advantage.
While current results put Premadasa ahead with 463,453 votes to Rajapaksa's 409,250, the vast majority of results outside of the North are yet to be released.
Update: 22:45 GMT
Gotabaya Rajapaksa is over 20% ahead of rival Sajith Premadasa on the 12 results announced so far.
Surpassing 200,000 votes, Rajapaksa is currently on 56.62% of the vote-share while Premadasa has 36.15%
Rajapaksa has won almost 66% of the Colombo postal vote with 21,717 votes while Premadasa took 25% with 8,294 votes.
A closer result was returned in the Trincomalee postal vote than the two Northern results so far declared as Premadasa won 56.79% of the vote with 7,871 votes and Rajapaksa less than 3000 votes behind on 36.72% with 5,089 votes.
Update: 21:15 GMT
The announcement of Vanni postal votes and votes from Nallur have given Sajith Premadasa a slight lead over rival Gotabaya Rajapaksa, with Premadasa on 56.46% of the total vote announced so far, to Rajapaksa's 35.85%.
Premadasa won over 86% of the vote in Nallur with 27,605 votes, while only 5.72% went to Rajapaksa - 1,836 votes.
Meanwhile in Vanni, Premadasa won 79.3% of the postal vote, although the result accounts for only 8,402 votes. Rajapaksa won 16% of the postal vote in Vanni with 1,703 votes.
Tamil politician M K Shivajilingam came 3rd in the Nallur vote, winning 659 votes and 4th in the Vanni postal vote.
The first result in Sri Lanka’s presidential election has been announced, revealing Gotabaya Rajapaksa winning almost 70% of postal votes in Galle.
Rajapaksa won 25,099 postal votes in the southern district - 67.48%, with rival Sajith Premadasa winning 9,093 votes - 24.45%.
The JVP’s Anura Kumara Dissanayaka won 2450 postal votes - 6.59%, while former army commander Mahesh Senanayake won 301 - less than 1% of the total postal votes for the district.
More to follow.