Mr Deby, who has been in power since 1990, won 77.5% of the vote and will serve a third term, it said.

Opposition parties boycotted the 3 May election, accusing Mr Deby of corruption, and called the poll a farce with a low turnout.

However, the Election Commission said on Sunday the turnout was 61%.

Darfur violence

Correspondents say Mr Deby's re-election was a formality given the boycott by the opposition, which accuses him of siphoning off oil revenues.

Four relatively unknown opponents gathered between 3.7% and 8.8% of the votes.

Despite the boycott, observers of the African Union and non-governmental organisations said the elections were largely "free, open and fair".

Mr Deby, 54, had gone through with the election despite a coup attempt by rebels in the capital N'Djamena three weeks prior to polling day in which hundreds of people were killed.

The African Union and the United States had suggested a delay given the coup attempt and the instability in Sudan's neighbouring Darfur region.

Chad hosts some 200,000 refugees who have fled the violence across the border in Darfur.

Rebel groups, which Mr Deby says are backed by Sudan, did not in the end carry out threats to disrupt voting.

Mr Deby's Patriotic Salvation Movement (MPS) rebel group seized power in a rebellion and he won elections in 1996 and 2001.

Opposition figures, including some who have fallen out of favour with Mr Deby, accuse former colonial power France of interfering to keep him in power.