MORONI (Reuters) - Police in Comoros used tear gas on Monday to disperse demonstrators led by opposition leaders protesting against what they said were fraudulent presidential elections, witnesses said, while observers said the whole vote was flawed.

About 300,000 voters in the Indian Ocean archipelago of 800,000 people took part in the elections, with results expected to be announced by electoral body CENI later on Monday.

Opposition candidates had said the Sunday poll was marred by irregularities including barring of independent monitors and marking of ballot papers before voting began, which the government denied.

Observers from the African Union, the Common Market of Eastern and Southern Africa, and the African Standby Forces of the East said the whole voting process was riddled with irregularities that led them to conclude it lacked credibility or transparency.

Protests led by opposition candidates started on Monday morning, with nearly 1,000 people chanting “Azali Nalawe” (Azali outside), referring to incumbent President Azali Assoumani.

Assoumani, a former military officer, is widely expected to be re-elected.

Soilihi Mohamed, one of the candidates, said their objective was to “to prevent the power to validate the fraudulent results of the elections”.

The demonstrators marched toward Independence Square for a rally before taking the direction of the Peoples’ Palace, the venue for the counting of results, a Reuters witness said.

Patrice Emery Trovoada, the head of the African Union observer mission, said their preliminary report showed that on voting day, there were incidents of vote counting being interrupted and police being involved in improper transport of ballot boxes.

“These malfunctions...have thus affected the smooth running of the voting and counting operations and therefore, the entire ballot,” he told a joint observers’ news conference.

The missions urge stakeholders in the electoral process to take part in a dialogue. It also recommended that the government set up a framework for consultations “to create and consolidate a climate of peace and stability,” Trovoada said.

Ibrahim Ali Mzimba, another presidential candidate, suffered a cut to his face during the protests.

“I think I was grazed by a bullet that touched my face,” he said.

Comoros experienced months of unrest last year as authorities moved to quell protests against Assoumani’s bid to extend presidential term limits.

People on the archipelago’s Anjouan island were angry that the move, which allowed Assoumani to participate in Sunday’s poll, would deny them the presidency under a system that rotates the post among the country’s three main islands.