Sri Lankan President Mahinda Rajapaksa has won a second term, defeating former army chief Sarath Fonseka with a 57.9% of the popular vote.
Elections Commissioner Dayananda Dissanayake confirmed that President Rajapaksa had received 6.01m votes, 1.84m more than his main rival Gen Fonseka.
Independent observers put overall turnout at between 70% and 80%.
The two former allies laid claim to the total defeat of the Liberation Tigers of Tamil Eelam (LTTE) in May but became rivals in a close-fought election campaign.
Mr Rajapaksa said he wanted to seek a new mandate for his plans to develop Sri Lanka by exploiting its geographically strategic position and encouraging foreign investment.
However, tension is high as troops have surrounded Gen Fonseka in the Cinnamon Lakeside hotel in the capital Colombo.
In a phone call with Reuters news agency, Gen Fonseka said: 'These people have surrounded the hotel with military and threatened my security people.
'They had a plan to surround us and take us into custody and I don't know if this is that phase of that particular operation.'
A military spokesman said there are no plans to arrest Gen Fonseka, but rather to capture around 400 army deserters with him who could pose a potential coup risk.
'They have booked 100 rooms. They are highly trained military people. We are suspicious about their gathering. General Fonseka has released nine deserters to the military police,' the spokesman said.
Mr Rajapaksa called the election two years early, hoping to capitalise on his post-war popularity to win a second six-year term.
