Some 300,000 voters were eligible to vote in the Indian Ocean archipelago, which has a two-round system for electing the president
Police fired teargas and rubber bullets Monday to disperse more than 100 opposition supporters as Comoros awaited the results of elections President Azali Assoumani is tipped to win, AFP correspondents saw.
Two people were injured -- a protester and a plainclothes policeman -- when the group including several candidates began marching towards the capital Moroni's Independence Square to protest alleged electoral fraud.
The country is awaiting the results of Sunday's presidential elections which the opposition claims was riddled with flaws.
Heavily armed soldiers were deployed to several key locations in the capital with orders to prevent unrest, Interior Minister Mohamed "Kiki" Daoudou told AFP.
Twelve people were slightly hurt in Monday's police crackdown including three election candidates, a hospital source said.
Sixty-year-old Azali's main rivals, the Union of the Opposition, allege that irregularities at several polling stations reported by the electoral commission on Sunday amounted to a "coup d'etat" and called for public "resistance".
An electoral commission official told AFP on Sunday that a dozen booths were vandalised during polling.
Witnesses said several stuffed ballot boxes were found on Anjouan island -- an opposition stronghold.
Some opposition poll monitors were also prevented from carrying out their duties, they added.
"The security forces have taken a stand for a government which has lost its legitimacy," said opposition Juwa party candidate Mahamoudou Ahamada.
Counting started Sunday night at the National Assembly under police guard and Daoudou, the interior minister, said the first results would be announced by early Tuesday.
"We have counted (ballots from) Moroni and surrounding areas," an electoral commission official told AFP.
The commission was waiting for boxes from Anjouan and Moheli, two of the three islands that make up the country, the source said, adding that results would be released within the legally required five days.
The army intervened during vote-related unrest on Anjouan that left one protester dead and several others injured, according to an election observer group.
Daoudou told AFP he had "never seen more transparent elections in our country".
'Some problems - it's not a surprise'
Azali's campaign director Houmed Msaidie described opposition claims of election fraud as "pathetic", accusing them of creating "a climate of panic to invalidate the electoral process".
"If there was fraud, they should go to the appropriate authorities," he told AFP.
Azali played down the incidents.
"I've been told there have been some problems -- it's not a surprise," he said after casting his ballot at a school in Mitsoudje on the main island Grande Comore, adding that he was confident of victory.
Some 300,000 voters were eligible to vote in the Indian Ocean archipelago, which has a two-round system for electing the president.
The mainly Muslim nation of 800,000 people is one of the world's poorest and most coup-prone states -- there have been more than 20 attempted or successful power grabs since independence from France in 1975.
The Supreme Court barred some of Azali's major rivals, including former president Ahmed Abdallah Sambi, accused of corruption, from running.
Azali staged the poll after Comorans voted in a referendum, boycotted by the opposition, to support the extension of presidential mandates from one five-year term to two.
The change upset a fragile balance of power established in 2001 that sought to end separatist crises on Anjouan and Moheli, and halt the endless cycle of coups.